This is a powerful question — thank you for asking it. Many people mistake a person’s potential for their reality. It seems clear that you are drawn to what could be in him but is not. The fantasy that this is a healthy love needs to be challenged directly. The relationship only works because it is lopsided. The more you do, the less he has to. As you rightly pointed out, this has never worked for you in the past and is not likely to work out now. The work you need to do is on grieving. Grieving adequately this misperception is essential. The longer you isolate yourself the worse it gets.
I would highly recommend you find a number of social situations to engage yourself in. Right now, you’re looking to be with as many people as possible — not sexually, but socially. The work is on grieving and learning to engage with someone properly. This has to be done in action — through events. Simply talking about it won’t provide the shift. I would try this approach on your own for a little while, but don’t be afraid to ask for some professional help if your own efforts have been paid off.