Sara, I think if you really mean this, then you have to quit talking to him so much. You can't let go when he is in your life daily. I know you care about him and believe me...I completely understand that you feel sorry for him...but he made his choice.
And that doesn't mean that you have to close the door on him forever if you don't want to. Is he just wanting to talk to you or is he wanting to get back together with you?
When I filed for D, my xh told me he still wanted to be friends. I told him I couldn't do that...at least not in the beginning...that I would never be able to move on if we did that. Luckily he has respected that request and I think it has helped me tremendously. I have noticed everytime I talk to him or see him I am in about a week long funk...so it is best for me to do NC. Maybe you can talk to your xh about this and go NC for a while.
Hang in there sweetie. About a month ago I found myself thinking about the sitch constantly...even crying daily...which I hadn't done in almost a year. It takes time.