My wife and I have had issues for almost the entirety of our relationship. For more than a decade, she has struggled with intimacy, compounded – we think – by a sexual assault 12 years ago. She then found out she was pregnant and, after an agonising wait, we confirmed the baby was mine and now have an absolutely incredible child together.

In the aftermath of all this, she had a combined diagnosis of PTSD and postnatal depression, during which time she ran up huge amounts of debt. She then had an affair with my best friend. I believe both were symptoms of her illness, but her behaviour since has prevented me rebuilding trust. I don’t think she is cheating on me, but I’m certain that in any choice between my happiness and her own, mine is considered less important and immediately discounted. I have now reached the point where I want to separate.

I believe there are many ways in which parents can cooperate and raise a healthy and happy child. I have offered a completely equal financial agreement (there is a large difference between our salaries) where I will help her to buy a house. I would then rent until she can put the mortgage in her own name. However she has threatened to fight for sole custody, refuses any financial help and has said she will move into a council house. While none of this is likely, it does not give me any confidence of a quick resolution – and any ongoing recriminations would only hurt my child.

I believe we would be healthier and happier apart, but I fear the repercussions could be so damaging that our child would be permanently affected. I also think I deserve some happiness, a little time and space to myself to heal.

I’m sorry you both find yourself in this situation. At times of threatened separation, people often bring past hurts to the negotiating table, which can make a clean and healthy break – something you crave – very hard.

I spoke to family psychotherapist John Cavanagh (aft.org.uk), who said you “can’t underestimate the impact a sexual assault has on intimacy”. Add to that your wife’s mental health and her ability to deal with situations where she doesn’t feel in control, and Cavanagh wondered whether you managed to really talk about it? Did she ever get any specialised support at the time?

Cavanagh felt you both had to deal with “lots of complex themes from the start. The uncertainty about the paternity of your child, and the added complexity that it could be a product of an assault … this all happened at what should [have been] a time of joy. How, as a couple, you spoke about that feels really important.”

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Were you able to make room for each other’s feelings at that time? The reason this matters is because times of stress usually follow a pattern. This pattern can be set by examples experienced growing up, so it could be a “corrective script or replicative one”, says Cavanagh. You can choose to follow examples shown to you, or try to challenge them and do things differently. In your case, he suggests, “that pattern may be to deal with conflict by separating”.

Cavanagh wondered whether your wife actually wanted to separate? “You’ve offered what sounds like a fair deal, but she’s communicating that she doesn’t want to take that up by refusing it,” he says. But it seems she doesn’t want to talk, either. You express a very clear idea of what you want, but what does your wife want – do you know?

He did have a technique he wanted to share: “We know some people really struggle with co-parenting after separation, but if they can remember the joint joy in what got them together, and in their child, then, when negative comments or thoughts come in, perhaps these good memories could be used to jolt them back to remembering they need to communicate well for the care and love of their child.”

There is no doubt you could both benefit hugely from couples therapy to help you separate in as healthy a way as possible. But whether your wife will go with you is, of course, another matter. I hope she does and that you can, with some help, come together in order to separate.

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