There are three of us in my relationship. Me. My partner. And my partner's psychoanalyst.

It started soon after we met. We were both newly separated – I was a single parent – and we had fallen in love with indecent haste. He was attractive, emotionally articulate and excruciatingly funny – but sometimes he had a dead look behind the eyes. He'd had a hard, complicated upbringing and seemed to be suffering from serious depression.

At the time he had just finished attending couples counselling with his former girlfriend – part of an agreement, instigated by her, to reach some sort of positive closure. The therapist had clearly also seen that he was in trouble and had offered to begin treating him individually. I encouraged him to take up the offer.

He didn't want to go to the first session. I had to push him. I remember saying to him: "Don't worry, you're not going to get a telling-off." When he came back the sense of relief was palpable. He emailed me: "The good news is that it was really helpful. The bad news is that he thinks I'm so fucked up I need to come five times a week for at least two years."

That was five years ago.

Unlike the couples counselling, which had been face to face, he would be on the couch. He would see the analyst at 8am every weekday morning. I missed our time together, but his reaction to the analysis was intensely positive – he was an instant convert, immediately beginning to tackle serious problems that had dogged him all his life. There were other positive aspects that radiated out from his treatment: it gave him, and therefore us, a vocabulary to talk about ourselves from the outset; and it helped him with the business of becoming a stepfather, universally agreed to be a very tricky brief whoever you are.

Soon I got pregnant. Ben was overjoyed – he had been desperate to become a father, pushing for us to get on with it quickly, as my reproductive window was closing. The pregnancy was a joyful time. But it was when I was in the very first stages of labour, which happened in the early evening, that I began to wonder if the analysis wasn't intruding on our lives a little too much. As he sat by my hospital bedside he asked me, with an urgent expression on his face: "How long do you think this is going to take? Do you think I'll have to miss analysis in the morning?" At first I thought he was joking – but he was being perfectly serious. I told him that if he went he would be miles away, with his phone switched off, and that if he didn't want to risk missing the birth of his baby he shouldn't go. Privately I was a little shocked that he had even asked.

When we brought the baby home I began to feel resentful. I was up all night feeding yet I could never have any extra sleep in the morning. My day began at seven sharp, when he would leave for analysis, followed by work and often work-related functions in the evening. I would get both children ready and take my daughter to school, baby in tow. Sometimes there would be three days and nights where I didn't see him at all except to sleep.

I realise, of course, that this is a very middle-class tale. What a friend of mine would call an "expensive problem". And I am perfectly aware that things would be worse if I lived in downtown Mogadishu. But it was my life.

I used to hear the door slam behind him in the morning and feel utterly abandoned. Yet when I raised this he told me it was all down to my own issues – my sense of being left as a child by my own father. Nothing to do with the loneliness and exhaustion that can come with having to cope with a tiny baby on your own. Apparently I was jealous because I wanted analysis myself. At one stage Ben insisted I look into it, but the referral – in which the therapist told me I would need to attend three times a week – was a disaster and I never went back. Seeing a therapist to discuss my feelings about his therapy? That way madness lay – even in north London.

There were other issues. Ben's morning session dictated the mood of the household. The analysis dictated when we could go on holiday. It was expensive. More importantly it meant there was no privacy within the relationship – obviously I knew I was being discussed in the sessions, but I wasn't allowed to know what was said because the sessions are sacrosanct. That confidentiality felt a bit one-sided.

Most of the time we did the usual things – we walked on the heath, criticising and gossiping about our friends and families and making fun of our children behind their backs. Then all of a sudden we'd be having a furious row sparked by something he would repeat from one of his sessions, in which I felt misrepresented. In the end I banned any talk about his sessions on the grounds that everything he ever told me would be, necessarily, taken out of context (the context being a conversation of approximately 230 hours a year) and would therefore probably be either hurtful or annoying. I also felt that, in a way, this gave me some sort of power and equality where otherwise I had none.

Still, the analysis seemed to be working for him and he began to heal his relationship with his mother and to kill off relationships with people who made him unhappy. I was still resentful about the mornings and the money, too, but less so. I believed in it all.

Our second child was born last July. As the labour began, he lay on the bed next to me with his arm round me. We were laughing about something. Then he gazed at the ceiling. "So, how long do you think this will take?" he said. "Will I have to miss a session?" It was the same conversation as before – though I gave it rather shorter shrift this time.

I was back home from hospital within 12 hours of giving birth and the next morning it was business as usual. I had to deal with the children and a new baby. Two breakfasts, two packed lunches, a breastfeed and a struggle to dress a recalcitrant toddler later, I literally had spots before the eyes. I called the doctor, thinking my blood pressure had gone through the roof and my kidneys were about to explode.

August soon arrived – the month when psychoanalysts go on holiday and all sessions are off. I remember this as a lovely, intimate time. After a tough night, with the other children still asleep, we'd lie in until eight in the morning with the baby in the bed with us. We visited his mother, who cooked us enormous dinners and we went swimming in the river near their house while she watched the baby and the other children. The countryside seemed to be in Technicolor. In the absence of another shoulder to cry on, Ben seemed more loving and attentive. (Though I am not blind to the danger of needing to be needed, I am also only human. If people are nice to you, it's nice – it hardly matters why.) He began to talk about stopping the analysis – I said I wouldn't ever demand it and that things ought to be done properly, but I wouldn't deny how happy I would be to have him to myself again.

Then came September, and the beginning of the fifth year of treatment. After the very first session Ben returned home detached, distant, churned up. He seemed to view all our previous conversations about him eventually stopping as me trying to sabotage his analysis. It was as if he had rejoined a cult that would never let him go, where anyone who questioned it was not to be trusted. The intimacy we had experienced in August vanished and was replaced with hostility.

I was furious. Not with him, this time, but with the process itself. With his analyst. Who was this cuckoo in the nest? This third party whose opinion was so much more important than mine? What was this process that effectively turned me into a non-person, even though I was so profoundly affected by it on so many levels? It wasn't just that Ben seemed to take priority, but that the process itself deserved to be taken more seriously than me.

I wrote a fantasy letter to his analyst saying that I was sick of being discussed without being allowed to know what was said and worrying about what misconceptions about me might be being fostered. It concluded with an invitation to him to fuck off, which I took great pleasure in blowing up into 84pt text, before filing the whole document into the trash can on my desktop.

Having never been a sceptic, I now began to doubt the process. I looked everywhere for advice for spouses of patients but found none, except a piece from the New York Times dated 1982 which concluded that the only way to survive was to have analysis yourself.

In desperation I turned to two acquaintances, both of whom have undergone analysis as part of their training to be therapists themselves. Both of them shifted about uneasily – almost guiltily. There was nothing they could say to help, other than to acknowledge that, yes, it must be very hard for the partner.

It was when I was going on about this yet again that Ben suggested I write this piece – he thought it would make me feel better. (In fact it was the middle of a row. "Why don't you write a bloody piece about it?" "Well, perhaps I bloody will!") I emailed the Tavistock Centre, the renowned NHS mental health trust, and was put in touch with a psychoanalyst named Philip Stokoe. What he told me provoked fury and relief in pretty much equal measure.

Wasn't it true, I asked him, that when one of you is in analysis there is a third person in the relationship, a lack of privacy and a feeling of two against one?

"Well, I think that is true. But it's complicated." Stokoe began to explain how the sessions work. "I'm the analyst. I am hearing from my patient a description of his wife or partner. My assumption is that this is a means of telling me about his inner world. It doesn't always feel like that, because he is thinking that he is talking about his wife. I think it's a real problem, and all analysts are aware that there is a danger to partnerships because of the way that stuff that belongs to the patient gets re-enacted outside that psychoanalytic dyad."

As Stokoe describes it, it is all about the twin concepts of "resistance" and "projective identification". Essentially it is a natural instinct to resist anything that might lead to change.

One key method of resisting is to project all the feelings within yourself that you cannot bear on to another person, usually the one nearest to you. As a baby or child this is usually your mother, father or siblings. As an adult it is probably your spouse.

"One of the ways that change can be resisted," says Stokoe, "is that instead of thinking about it between the sessions, you go back to acting it all out by engaging it with someone else who will then become the part of you that you don't want to look at, so then you can have a row. You are not working through an internal conflict, you are creating what appears to be an external conflict. It's a problem."

What I think he's saying is that I am a non-person who exists only as a representation of Ben's inner world, but who must nevertheless live my life as a mopper-up of crap that is thrown out by his sessions.

Well, yes. That's why, as Stokoe explains, "Freud in the beginning forbade people from having sex if they were in psychoanalysis, and said it wasn't a good idea to have a relationship. He did understand that you couldn't really do that. But he realised from the beginning that it was an issue."

My already simmering anger is beginning to bubble over. Surely in a discipline that can only exist if it looks at itself, this huge problem is acknowledged. Surely someone in the psychoanalytic community has thought to put together some sort of fact sheet, advice page, support group, helpline – something to show that someone cares what you, the spouse, think and feel?

"This is a really appropriate and good question," says Stokoe – the kind of opening that you know means the sentence isn't going to end well. "We don't do enough to help spouses think about it. The problem is a very simple, technical one. If I'm talking to my patient about his mind and he keeps on insisting I am talking about his relationship with his wife it would be making a terrible mistake to say: OK, bring your wife in."

Look, I'm not stupid, I say. I know that the sessions are one on one. I'm talking about advice.

"Do we currently send out advice? No, we don't. Places such as the Tavistock are available to spouses. If they are having a problem with what seems to be happening to the patient, they can ring and one of our colleagues would talk about what's going on."

But is this advertised?

"No."

In which case someone like me wouldn't dream of doing it – it would seem to be overstepping the boundaries and a complete no-no in shrinky etiquette. And anyway, I press on, aren't therapists only human? Surely after years of talking about someone's partner, they begin to feel that they know them and can slip into talking about them as if they do.

They shouldn't, says Stokoe. "By and large [analysis] happens in private practice. I am afraid that some of my colleagues have made mistakes like that. But now," he reassures me, "all analysts have to be part of CPD – continuous personal development. It's only in the last five years that we have insisted upon this. They have to take their work to colleagues – it helps us not to make mistakes. You get lazy if you are isolated as a therapist." In other words, you can start to talk about the spouse, say, as if you know them, instead of talking about them as a projection of the patient's mind.

What is more, says Stokoe, he knows exactly what I'm talking about. His wife, also a psychoanalyst, had a very adverse reaction to his own analysis, which he undertook while in training. "She certainly felt that I went through a period of being really quite mad and thinkingthat she was out to get me. I felt very, very paranoid. I came home believing that she was looking for any excuse to attack me. She got really quite fed up and wanted to speak to my analyst – which I thought was evidence that she did want to attack me. But I was acting out something very difficult in the analysis [at the time]."

What about this business of being a non-person? I keep returning to this; I just can't let it go. Doesn't this all essentially mean that for the duration of the analysis nothing is really real?

"I think that's sort of true. But what I would say is that, first, not everything that's going on between the couple has anything to do with the analysis, and secondly, I am also a couples therapist, and very often psychoanalysis does expose some of the faultlines of the relationship. It's likely to reveal any of the hidden problems that might not have been noticed."

"But," he adds, a trifle defensively, "I don't think that it will provoke a breakdown of the marriage that wasn't on the cards. Even if the patient is very much distorting the story about the relationship, the analyst will pick it up."

Perhaps he can tell what I am thinking, which is that if an analyst can take any kind of view on the relationship while only knowing one of the partners, all this stuff about "keeping it in the room" is just rubbish. Hmmm, I conclude. So what advice could you offer a spouse whose partner was about to be psychoanalysed?

"A good bit of advice," Stokoe says, "is to be prepared for the way that stuff that should be part of the analysis will be brought into the marriage. I think you do have to put up with it, but you don't have to put up with everything. Be on your guard for stuff that belongs to the analysis being dumped on you, and say to your partner: 'This isn't to do with the relationship – take it to your analyst.' We do know that these things are a strain on the spouse. Particularly the financial and time issues."

By the end of our interview – which ironically lasts exactly 50 minutes, the same time as a psychoanalytic session – I am relieved. In many ways Ben and I have handled this pretty well, considering what might have been. I assume this is also in part due to the skill of his own analyst, which makes me feel more confident about the future.

I rush to tell Ben everything I've learned. But he's uncomfortable hearing about it.

"It makes me feel weird. I don't like the feeling of being discussed by someone who doesn't know me," he says.

"Welcome to my world! Now imagine this happening five days a week for five years."

"You're just doing this whole thing to make me know how it feels," he says.

"Yes!" I say triumphantly. And perhaps, in some way, I have now finally got a word in.

Names have been changed

• This article was amended on Sunday 4 December. In the original, "danger" was misspelt as "benger" on two occasions. This has been corrected