I'm very glad you've overcome it and in time I hope it's just the past, entirely. I can relate to much of what you wrote and I'm currently going through my version of it all. I too, feel like a puppet on strings that is not allowed to have my own life separate from her.
I've self-isolated and detached myself from frenemies in over abundance as well. They've always fed off of my positivity or support and alienated me when there was a sense that I ever needed it in return. So, I can relate greatly. Especially to your latter statement of forever being single to avoid all of the turmoil.
I'm trying to see all of this as a blessing in disguise, perhaps that should be applied to you as well. :)
Try to stay hopeful, yeah? :P
The way I see it, every life is a pile of good things andů bad things. The good things don't always soften the bad things, but vice versa, the bad things don't necessarily spoil the good things or make them unimportant.- Doctor Who ; Vincent and the Doctor