He discovered messages on my phone and so I sat him down and poured the whole sorry tale out to him, feeling I was stamping on his heart with every word. I spent a lonely Christmas at my mother's house with nothing to do but wonder how I had got myself into this situation. I started therapy, and learned just how dysfunctional my life had been, and so little wonder I kept making new problems for myself.
I began writing everything down, to help make sense of it, first for myself, then for others.
As I have come to learn, most of those who grow up in a dysfunctional relationship are condemned to seek them out forevermore. In adulthood, I had become a rather complicated girlfriend, each relationship beginning well, but then growing fractured and ending badly.
I am bound to say, though, that I wasn't solely culpable. I ended up marrying one of these complicated boyfriends.
I was a latecomer to counselling, having previously considered therapy a largely American pursuit. By the time I reached that landmark age, without children and in a marriage that was beginning to lose its fairytale glow, my daily life was beginning to feel not unlike a soap opera.
Call 08 or visit Telegraph Books The Big Short, the film adaptation of Michael Lewis' book of the same name about the causes of the financial crisis, opens in UK cinemas this weekend.
From the very first meeting, the guilt racked through me.
We would meet in hotels, have sex – mindblowing sex - and then the realisation that what I was doing was irrevocably wrong would set in.
Bringing it to life brought only complications, albeit occasionally exquisite ones.
After a couple of months I had to end it – and it was after I had made this decision that my husband found out.
It's taken me a good while to fully come to terms with what I've done, to understand how easily I fell into the previously unknown world that I would regrettably come to prefer to the real one.