The pain will stop, I promise. I won't lie and say it'll be quick, but it will go.
When my ex moved out my doctor suggested grief counseling, which helped. Not that I'm saying mourning a death of a spouse is the same, but you are mourning the death of your relationship. There are the same five stages, anger for me lasted the longest.... it sounds like he is in denial too... it is very difficult to let go, and although he no longer loves you, he sounds like he cares for you, you have shared a lot and he cannot shut his feelings off for you, giving you hope is a way to soften the blow.
I went to RELATE. Maybe see if there is something like that still.
Good luck, and come to SWK meets with the kids and see the otherside of this.