My friend, you're taking all this because you feel you don't deserve any better! And of COURSE YOU DO. And you're taking it because you figure you can't get anyone else -- and OF COURSE YOU CAN. I know you don't want to be alone, but just because you break off with this guy doesn't mean you'll be alone forever.
First you have to learn to love YOURSELF. He's walked all over you to the point that your self-esteem is in the toilet! You've got to get it back. And the best way to do that is to seek counseling. A good therapist will help you do that.
Plus you have to learn how NOT to be a doormat anymore -- take your power back, and get up off the floor. You can't be a doormat if you're not laying down.
Talk to your doctor and have him refer you to a good therapist. You need someone to talk to, so you can find out WHY you're putting up with this kind of treatment. Your doctor will know who to send you to.
In the meantime, kick this guy to the curb. You'll grieve for the relationship, but NOT for him. He's not worth grieving for.. God bless, my friend and PLEASE take care of YOU. Hugs, Lee