Sex File: We've separated but still sleep together 

'Ending a marriage is not one single gesture.'

My husband and I agreed to separate in the middle of last year after 13 years. However, we're still living together while we sort out arrangements with the kids, and find ourselves sleeping together on and off (sometimes once a week). It's definitely not make-up sex, I'm clear I want to move on, so why can't I stop?

There is clearly no one waiting in the wings for either of you — if there were, this wouldn't be happening — and so, despite your certainty about wanting to move on, the door that leads back into your marriage is still slightly ajar. 

Ending a marriage is not one single gesture. As you are realising, it involves the cutting of multiple ties: emotional, legal, economic, co-parental, sexual, psychological and social. Each of these can have its own time frame so, for example, the emotional split may be complete but the financial one drags on, and the longer a marriage, the greater the number of bonds that need to be severed for complete separation to be realised.

You are half in and half out of something that has been the fabric of your life for more than a decade. You share kids. You share a home. You share a life. And as you negotiate your impending split, you also, inevitably, share feelings of sadness, anxiety or regret. When those waves of emotion wash over you, the person who understands those feelings the most is the one that you are trying to leave. If the sex brings solace, not confusion, and the situation is not bothering either of you, I wouldn't worry too much about it. Splitting up is hard, and although your situation feels confusing, research indicates that it is a pretty normal strategy for decreasing the stress of separation.

In 1994 psychologists Cindy Hazan and Debra Zeifman conducted a study which showed that, perhaps counterintuitively, sexual contact with a former partner allowed people who were struggling with a break-up to accept their separation and reduce their anxiety levels. In 2012 Ashley Mason and David Sbarra of the University of Arizona extended this research by exploring psychological adjustment in a group of 137 married men and women who had recently separated. The study revealed that for people who were struggling with separation, non-sexual contact with their ex-partner amplified their distress, whereas sexual contact decreased it. The researchers explained that seeing a former partner activated the "attachment" system for both groups, but only the people who had sex were able to get those attachment needs met.

Only you know why you ended up in this situation, but it is worth reminding yourself that the relationship you are having with each other now is probably better because you are getting all the good bits (sex) without the bad bits (endlessly circumnavigating the possibility of divorce). People rarely anticipate how disruptive, costly and psychologically painful breaking up a family is, so if the sex is still good and your relationship has improved, it is worth considering giving the marriage another shot.

Right now, sex is helping you both to cope, but sooner or later one of you will meet someone else — and if that person is not you, failing to complete the separation process may feel like a bad decision. Everyone warns about rebound relationships, but once you are certain that you don't want to go back, do everything you can to go forward.

• Send your questions to [e-mail]