Sex File: I still fantasise about my ex

I keep thinking about a past relationship, is this something I should act on?

Mon, 13 Jul, 2026 - 07:44

Suzi Godson

My ex and I split shortly after our daughter was born - it was a newish relationship, a surprise pregnancy and we decided quite quickly that we made better co-parents than a couple. Our daughter is now 10, and since I split with my subsequent partner of eight years, I've found myself fantasising about my daughter's father non-stop. Is this something I should act on?

The brain is such a powerful instrument that it can manufacture a state of involuntary obsession with another person seemingly out of the blue.

Suddenly, you can't stop thinking about a specific person. Your heart races. You have sexual fantasies about them. And yet they are often completely oblivious to the fact that you are even thinking about them. This phenomenon is called limerence, and it describes a fixation that is often one-sided and is usually predicated on uncertainty. Not knowing how the other person feels leaves the door ajar and where there is possibility, there is hope.

It is not a coincidence that your thoughts have turned to your ex at this particular point in time. When you feel unmoored, it is incredibly common to revisit past relationships in search of solace. Sex with the ex is almost a cliché, but when you've put just enough distance between you and the reasons you split, a quick rummage in the romantic imagination will unearth those discarded rose-coloured glasses. In psychological terms, this is known as fading affect bias. When people go through difficult life experiences, negative autobiographical memories fade faster than emotions tied to positive memories. Getting rid of painful feelings is a form of self-preservation that helps you to regulate your emotional state and recover from trauma.

A happy split can give rose tinted glasses

When it comes to difficult and damaging break-ups there is normally enough trauma to prevent people from behaving irrationally, but when you have had a reasonably amicable split and successfully co-parented a child, it is a lot easier to idealise what might have been. Your daughter makes all the what-ifs take on a much deeper significance. What if you had just given yourselves time to adapt to the surprise pregnancy and grow up a bit? What if you had tried a bit harder or been less defensive? Maybe you and your ex and your daughter could have been a happy family?

Fixating on the past is almost certainly a way of getting through a difficult period but it is also a way of avoiding the present. The man you have just split from was part of your life for eight years and by extension he will have played a part in your daughter's life too. On some level you may feel a degree of guilt at the fact that this break-up means that she has lost a relationship with a man who was a consistent figure for most of her childhood. And although you probably aren't thinking about what your future holds right now, a relationship with her dad might seem like a better and safer option than bringing someone else into her life.

Viewed in this context, fantasising about your ex is more complex than simple self-soothing. However, as long as you prioritise your daughter's wellbeing and remain realistic about the possibility, or more likely the impossibility, of resurrecting a relationship that ended for legitimate reasons, your fantasy is unlikely to do any harm. Fortunately, it is also unlikely to last, but until reality bites, it may just give you the space you need to adjust to life as a single parent for the second time.