My partner and I have been together for 15 years. About six years ago, he started a relationship with another woman, which I felt jealous about, but I decided that I loved him too much to leave him. He says he loves both of us equally.

Recently, he told me that he is polyamorous and is now in a relationship with a third woman. He says he needs his space, and that he doesn't want to share his other lives with me. He is very caring towards me, except when it comes to discussing this issue. We enjoy each other's company, but I constantly feel the presence of a third or fourth person.

I can't stand the constant dishonesty that he indulges in to accommodate these other two women - he says he needs to deceive me as he believes he will hurt me if I find out about the specifics of his other relationships. We constantly fight about this and have had a very unhappy past few years. I feel I have a right to know about his life, especially because, by his own admission, the main thing he discusses with the other women is how our relationship is going downhill.

I feel as if my privacy is not being respected, and I am expected to just learn to live with the fact that he has relationships with other women. How do I decide whether I am ready to accept that he is "different" or whether I am too jealous to ever be happy in this situation?

Polyamory needs mutual consent

I have had polyamorous relationships for 30 years, and believe polyamory is about openness and having multiple relationships with the knowledge and consent of your partner, rather than by deceit. You are in the passenger seat here and are clearly unhappy about the inequality in the relationship and lack of shared commitment - there's no point in trying to adjust to polyamory when it is not the fundamental problem. Start being more assertive now. Leave.
JH, via email

He doesn't love you as you deserve

You have given your partner mixed signals about how accepting you are of his other relationships: you tolerated the first "other woman", and have complied with his lifestyle generally since. The problem here is not that he defines himself as polyamorous - it is that he is polyamorous and you are not. When will you realise that this man does not love or respect you in the way that you deserve?
GPA, Birmingham

It's a power struggle you're losing

Anyone who insists on having more than one relationship does so because they relish the power they have over their partner(s) and also fear, or want to avoid, any real intimacy. He's not "different" - he's just trying to justify being deeply selfish. Could it be that this man wants to end his relationship with you and is hoping his unreasonable behaviour will prompt you to finish it? Few women would put up with what he is putting you through.

Ask yourself if you enjoy the hurt and fighting at some level. What stops you from ending a relationship that causes you such distress?
Name and address withheld

Admit you're unhappy, and leave

Like you, I had a partner who had another woman. We both knew about each other, yet chose to "share" him. I left him last year and met a man with whom I am deeply in love and we are already planning to get married. I realised that despite my rationalisations about being able to handle a polyamorous relationship, I couldn't; it made me miserable and I realised I'm worth more.

Fear of being alone seems to stop you from moving on, but you clearly want someone to love you and you alone. Don't settle for anything else.
JM, London

It's not polyamory, it's infidelity

I wonder which friend of your partner supplied him with this jolly word, "polyamory" to explain his infidelity? Your passive reaction is understandable; in that you are afraid to let him go, but you're implicitly giving him permission to cheat. He is being completely disloyal to you as well as unfaithful.

It isn't possible to have emotional intimacy with a group of people, and it sounds as if you are not even the one with whom he is most intimate. Summon up all your strength and self-esteem and make a new life without him. By the time I left my husband, he was also involved with two women and I had wasted years waiting for him to settle down. My life improved immeasurably when I faced up to the whole sorry mess and left.
TS, Deal, Kent

There's no respect nor self-respect

He certainly isn't "different" - plenty of heterosexual men are tempted to give free rein to their egos and testosterone by sleeping with any woman who expresses an interest in them. However, most men choose not to, out of love and respect for their partners.

This man regularly breaches your trust and privacy. He is showing you no respect because he senses that you have no self-respect. You should have shown yourself a little more love six years ago by ending the relationship when he started having affairs with other women. Don't allow him to do you any more harm.
M, via email

Dishonest? He's just a hypocrite

Your partner is not indulging in dishonesty, it's pure hypocrisy. He has set a double standard for your relationship: you are not allowed to question his behaviour, but he is free to discuss your relationship with his other partners. How would he feel if you were having other relationships and discussing him with your lovers? Polyamory is based on mutual consent, but your partner has foisted this situation upon you, and you have agreed to put up with it. You deserve an equal and respectful relationship - you are being emotionally abused and controlled. Do yourself a favour and leave him to his other relationships.
RN, via email

What the expert thinks - Linda Blair

I suspect many of us are "polyamorous". There's nothing unusual about feeling sexually attracted to more than one person at a time - in that regard, your partner's not unusual. However, the way people react to their amorous feelings is a measure of maturity, self-control and their sensitivity to others. In that sense, your partner is behaving selfishly, immaturely and insensitively. Not only does he allude to the manner in which he satisfies his sexual desires, but he also titillates you by telling you just enough to arouse your interest.

Note that your partner never offers you anything except innuendo - it's likely that he creates this uncertainty to encourage you to goad him for more information. You need to step back and think about this pattern of interaction, and why you seek to maintain it. Would you feel happier if he told you everything? He's withholding, and you're pushing for something that won't really make you happy.

I hope you can now see that there's a bigger problem between you than either the possibility of your partner's infidelity or your jealousy. Your relationship appears to be based on deliberate hurt and negativity. That is, you push him to tell you something you know will distress you, and in turn, he deliberately exploits the power you allow him to have over you, and for more than six years, you've done nothing to break this pattern. You've neither ignored his "other life", nor declared an ultimatum. His response has been to enlarge his scope for upsetting you. The result? Neither of you are happy, and yet you remain locked in confrontation.

If you really want the situation to change, you must stop expecting that change to come from someone else. Your partner's already told you that he's not willing to behave differently. Therefore you must either accept things as they are, or decide to reject the status quo wholeheartedly.

However, before you can make any truly satisfying changes, you need to take time to decide - in clear and definite terms - how you wish your life to be. The reason that this is so important is because change without direction is ultimately as unsatisfying as feeling stuck. One way to become aware of what you want is to "fast forward" and imagine how you'd like things to be in 10 or 15 years' time. How do you see yourself? How do you hope to be feeling? How do you imagine you'll be spending your time? Do you wish to be still locked in these circular altercations with your partner? Given that you're the one who must make any changes, what are the steps you'll need to take to achieve your vision for the future?

In order to be happy, it's not necessary to have a partner or to have any particular person or thing at all. It is, however, necessary to assume responsibility for your own happiness, and to establish principles for the kind of life that will make you feel proud of yourself.

Once you've taken the time to establish what's most important to you, you'll be able to decide whether you wish to remain with your partner, and if so, on what basis you're prepared for the relationship to exist.

Next week

I am 34, and have been with my partner for nearly three years. Although we argued a lot at first, we worked on our issues and now have a very "comfortable" relationship. We bought a flat together last year and co-exist very happily most of the time. I would like to have a baby and am conscious that I'm not getting any younger. However, for the past year I have fluctuated between wanting to have a child with this man, and not being sure whether he is The One.

When we first met, I was unhappy, lonely and a bit wild, and he avidly "rescued" me. I thought at the time that the best thing for me would be a relationship, so I let him. I have since worried that my choice was propelled by need rather than desire, although I recognise that I am the happiest and most balanced I've been for years.

The problem is our sex life has never been brilliant - at one point I even felt my sex life was over. I had a brief affair a few months ago, which assured me this was not the case, but I'm aware that sex isn't everything and don't want to repeat this behaviour.

I love my partner, but I am not sure I'm in love with him. I'm plagued by the thought I could find someone who ticks all the boxes. But time is ticking, and I'm afraid that if we split up, I would miss him terribly and not find my ideal partner in any case.

Should I stay and work at our relationship, or leave now before it's too late for each of us to find Mr or Mrs Right?

• Private Lives appears every Thursday. You are invited to respond to this week's main problem. If you would like fellow readers and Linda Blair to answer a dilemma of yours, send us an outline of the situation of around 250 words. For advice from Pamela Stephenson Connolly on sexual matters, send us a brief description of your concerns. All correspondence should reach us by Tuesday morning: email private.lives@theguardian.com (please don't send attachments) or write to Private Lives, The Guardian, 119 Farringdon Road, London EC1R 3ER.