I think about this all the time.
My friends and family who know my ex say they think he really did love me. Depends on how you define "love," I suppose. For a long time after BD and his move out of our home I kept thinking that he still loved me and would snap out of his crisis. But with 18 mos since BD, I've been able to get some perspective on my own issues as well as my ex-H's and although I know I truly love(d) my ex, I did not always show it in the best ways. I wonder if he ever truly had the capacity to love anyone, because he struggles to love himself. I think perhaps he idealized me and used my love to validate himself. When my love could not fill the hole in his soul, he stopped idealizing me and just saw me as the imperfect person I am. But that made him lose faith in me and himself. OW came along, desperately lonely and needy and willing to do anything for a BF, and he could once again idealize someone. The day he realizes she can't fill the hole either is coming. It may be months from now, or years from now. It may result in growth for him or more running. Don't know how I'll feel then.
Bird
Everything will work out ok in the end. If it doesn't, it's not the end.