I realise I'm late to the conversation here but I can relate to this. I'm going through this at the moment. I've been stung badly the past few relationships whether it be a sudden end or just being mistreated by someone who is a narcissist and thinks it's ok to emotionally cheat on you.
Anyway this isn't about me, I just wanted to say I can relate although I don't think they are evil. For me I feel like there must be something wrong with me as there are so many people out there having beautiful caring and loving relationships and I want that but it feels so far from my grasp.
I guess don't necessarily give up on them, maybe one day you will hit lucky like so many others have done. The other thing is you're tarnishing all relationships, I can tell you now that I would not be alive today if it wasn't for my daughter. She is what keeps me waking up every morning and the relationship a parent and child have is truly beyond compare. Then there are friendships too, some can burn you but some can really be there for you when you need them to be.