It took me to catch the ex cheating to leave, but like your H, my ex just wanted to be left alone with his addiction at the end. He didn't even flinch when I left. He didn't cry, ask for me back, didn't seem sad. Nope, all he cared about was his sporst and his married affair partner and hunting new women.
I was out of the way, so how great for him that he could continue in his sickness. And yes, this is the part that ripped out my heart the most. I was devastated and he just grinned and said "ok, we're over"
And imagine, he had already been sober close to 2 yrs when I left him
It took him 2 months after I left to join a step group and lord knows what prompted him to join that?!
In any case, YES, they love their pain and addiction MUCH more than anyone in their lives.
Sad part is, I know he loved me but his mental illness takes everything from him!