LW is being alone so much more worse then being in this relationship with him? Like Polly said, you haven't gotten to a good place with yourself. If you truly believed you weren't a "hateful slut" you wouldn't put up with the nonsense. Deep down you feel like you've found someone to love you in spite of you being "awful". Been there done that. This man is going to destroy your self esteem and whatever sense of self you have. Please know that you deserve better, random strangers on the internet can see your goodness and want better for you. Please want better for yourself. Trust us he is not the only man who could love you. I'm wishing you strength so you can end this relationship.
As Polly said please go back to therapy. Therapy is not a one and done situation. As she said, things change and you have emotional roadblocks. If therapy worked the first time it can work again.
The advice to actually feel your feelings is spot on. If you're uncomfortable verbalizing your feelings get a journal and write and write. You're not trying to get over your feelings, you are trying to work through them. They are you're feelings you get to own them. Live with some of the pain, cause you'll be surprised what great things can sometimes lay on the other side of that sadness.
I've never lost someone close to me. But I do have a mother who only allows me to be "Happy". Like Polly said you need to create some distance with her. She is not the person you can truly lean on, because it ultimately comes back to a place of "Get over It". Forgive your mom for not being what you need. And embrace the things that she can give you. Wishing you all the best!
LW please there is absolutely nothing wrong with you! Trust me I'm one of those women who would have let the guy come over and wasted a bunch of time and energy on a f*ck boy. You're dodging a real bullets by having these guy bail early. Trust me being in a relationship with that kind of guy is 10x worse and you can also feel just as lonely in that relationship just as easily as being single.
What I'm trying to say is you need to follow Polly's advice and keep doing what you're doing.