My fiance and I have been together for 18 months, but we haven’t seen each other for almost a year due to Covid restrictions. He had a four-year relationship before, with a girl he claimed he didn’t like that much, saying they always argued. At the beginning, I was totally fine with this, as everyone has a past. However, things started to change after I saw some pictures of them together and over the past few months I have started asking him all kinds of questions, such as, “Did you go to that place with her?” and, “Did you try this sex position with her?” If he says no, I’m OK, but if the answer is yes, I normally end up crying and blaming him. I know it’s not healthy, but I always bring it up in our daily call. It has become an obsession. No matter what we are discussing, I can always bring it back to his past. If he gets impatient, I get more angry.

I can feel this is affecting our relationship and I want it to stop, but I don’t know how. We can’t create new memories right now. Can this issue be solved only once we can meet up again, or is there a way to fix it before then?

It’s great you are questioning your behaviour and want to stop it, because it is bordering on the obsessive and isn’t bringing you peace. You didn’t say how old you are or what past relationships you’ve had, and whether this is how you’ve behaved in them. What was it about the photos that made you change from being OK with his past to not?

When you don’t see someone for a long time, or have day-to-day contact, it can be easy to fill the gaps with worst-case scenarios, if you are so inclined. But why you imagine the worst is what we need to look at, as well as what answer your boyfriend could give that would make you feel better. If there isn’t one, then what you seek is outside his gift, and within you.

If there’s no genuine reason to mistrust your partner – and nothing you said made me think there is – then why do you want to find fault? Is it a way to protect yourself? And if so, from what?

I went to Nicole Addis, a psychotherapist. She said sometimes people with trust issues might want to look at their early childhood attachments: how they were made to feel when they were little; if the love they received was conditional. These are all things that can affect our ability to trust as we get older.

People who have had difficult attachments with a parent can go on to self-sabotage their relationships once they reach a certain level of intimacy or involvement, because they can find it overwhelming (after all, being close to someone in childhood resulted in pain). They are then the architects of the failure of that relationship. In these cases, no answer will ever be reassuring enough, until the person has done some work on themselves. We have no idea if this is relevant in your case but if it’s something you recognise, you might want to explore this further, maybe with a therapist or a good friend.

Whatever the cause, I asked Addis for some practical tips for you. She explained that when something makes us feel afraid or threatened, we stop thinking rationally. We panic. Addis suggested looking at what triggers you, trying to stay away from that if possible, and taking a deep, calming breath. “Bank the facts, educate yourself with reality,” she suggested. “Your fiance is telling you there’s nothing going on, and there’s no evidence to the contrary, is there?”

Try not to get carried away with what might go wrong. This won’t be easy but it’s worth persevering with. If you feel you’re going to start asking lots of questions, maybe (nicely) end the call and talk to a friend: let them hold your angst about this instead. You need to break the cycle of starting conversations that bring no relief; it must be exhausting, for both of you. Maybe replace the daily calls with writing each other an email on alternate days? You’ll have more control over what you say and you can go back over your words and edit.

This will probably get easier to manage when you see each other, but if you are prone to this behaviour, it’s worth seeking out the root of it because otherwise it may not go away completely. In the meantime, what would happen if you talked about things you’ve done together, or plans for the future? What if you made the conversation about the two of you instead of about him and someone else? Maybe that actually makes you more uncomfortable.

• Every week Annalisa Barbieri addresses a family-related problem sent in by a reader. If you would like advice from Annalisa on a family matter, please send your problem to ask.annalisa@theguardian.com. Annalisa regrets she cannot enter into personal correspondence. Submissions are subject to our terms and conditions

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