If all your relationships have toxic drama, the common element is you. I say kill the problem at its source. (No I don't jesus balls please ignore that. Tf is wrong with me.)
Sometimes nice people attract parasites because they're easy targets to leach off. For some nice people, parasites are their type and they can't help being attracted to them.
It's good you're breaking these shitty relationships off instead of resigning yourself to them. That takes motivation, courage and follow through--all things severely depressed people struggle with. Just keep at it. 98% of everything is shit so it might take decades to find someone worth a damn but you'll never find a decent partner if you don't keep up the search. 🙏