Remember this, too. He is not the only source of comfort and companionship out there (and no, I'm not suggesting the college kids). There are mature, decent men who would LOVE to find someone as kind, compassionate, strong, and funny as you.
Not suggesting for a second that you should be out looking for one right now. But having the vision of that as a possible future consideration might make it a little easier to let go of this sad, damaging relationship that is not likely to ever give you what you need and deserve. Desperately holding on is no way to live.