So tell us why. We can help you stay strong.
Because for many years he had shown me no affection. I couldn't talk to him about anything other than the superficial as he would quickly get angry and defensive.
He was often short tempered and would not speak to me for weeks after some arguments. So I would go round wjth the most awful pain in the pit of my stomach. Eventually I would send him an email
asking him to start speaking again, and he slowly would, but we were never able to discuss what had happened. He was critical and blaming.
Because everything was in his name and I felt no sense of security about the future. He had also in the past purchased a property and not told me about it for about 10 months (and wouldn't have unless I had found out) so I didn't trust him.
When he realised that I was serious about the divorce (before that he was utterly dismissive - of that and of anything I might think in generally), he tried to ask me to stay - some things were heartfelt and some were very manipulative. When that didn't work (because I didn't trust that all our problems would magically disappear) he seemed to find someone else (while we were still living together) literally within nano seconds. So there were very long and very late intimate sounding phone calls and there was his showering to go out. Very painful.
During a lot of the divorce he has been very unpleasant. I have been shouted at, called all kinds of names, and accused of various things. He also told my solicitor that I have "never been able to look after the kids' best interests and that he can't see that changing" 
. Also that I would one day "make the effort to find a job" - I do have a job, just not well paid.
But now that the separation is slowly being implemented, I am in a lot of pain. I remember all the things I do like about him, the fact that for a long time we were friends, and also the crap things I have done which haven't helped. They don't change the fundamentals however, and especially that we were not able to discuss anything. Or the fact that he would sometimes fly off he handle and be really horrible, so there was a fair amount of walking on eggshells, especially at weekends. And how he showered the kids with affection and very obviously left me out in the cold. And now he is apparently showering someone else with affection and I can't believe that this person (who was on the phone with him while he was in my house - if someone went in the room he would just stop the conversation and hang up) is now with my "husband". It actually feels like a nightmare.