Limey - you deserve a diminutive.
Just read your original post - so sorry about your marriage; is it definitley the last straw? Is it worth trying the relate route? I think it probably is, no? (And counselling for yourself too, I am doing this, so is Mummy BB, not sure about the other slut sisters, but they have slightly different situations.)
I say this because my OM started because I had had problems in my marriage for a long time, which dh knew about but didn't want to face up to. One of them was that sexually our marriage was a disaster.
Whilst dh doesn't know about OM, he knows that I was very tempted to assuage my cock cravings elsewhere......
And now, after 18 months of my saying that things were not right, he has finally seen the light and we are trying Relate. I am not wildly optimistic, for a number of reasons, but I want to try and give it a go.
The obsession thing I can totally relate to, the original ennui and self-esteem not particularly, although my s-e has plummeted hugely as a result of OM's subsequent spurning of me and more, my own ridiculous behaviour. My biggest problem at the moment is that I seem to have transferred my affections from dh to OM, so that, for instance, whenever anything goes wrong in my life, I immediately want to contact OM. This is clearly delusional, as we only had one night together, but it is the way it is.
Sorry that was incoherent and not wildly helpful. Yes, RELATE, that was my point.
Oh and you have done very well to delete him from your phone. I still haven't managed to do that. I tried today, but failed.
Mummy BB hope you are doing ok,
and the other silent slutty sisters.