preggasaurus I read your entire post not realising you had said "ex" and after the last paragraph I had to scroll back up to make sure it was in fact your ex and was so relieved to see he is. That's just plain scary. Awful. How excruciating for you.
As for me, I won't go into detail as to what I've forgiven DH for, but he's had many issues that have been self sabotaging and in turn deeply affected the family unit. I like to think that I helped him through rather than forgave as such, although he caused me insurmountable pain and stress at times, I understand he was battling some very wicked demons.
I'm happy to say those days are well and truly over with now and upon reflection he's damn lucky he has someone with as much empathy as I do (too much perhaps for my own good) because most would have left for good.