Well, this was my first relationship so I have only just learned these things about myself in a relationship. I now too know that it isn't for me, nobody deserves to be with a piece of shit like me.
I'm going to disagree with you here. You are not a piece of s£&t. You are very thoughtful, kind and caring - you are practically the first person on here to answer any new thread offering help, kindness and moral support even though you are feeling unhappy yourself.
That makes you a valuable, special person with enormous capacity for empathy and caring.
Also you can't judge really 100% what all relationships will be like based on a few. Do you buy the first pair of trainers you try on?
The first pair of jeans?
Sometimes we are only meant to know people for a short time and they teach us a lot, other people we are meant to know a lot longer.
Please be a bit nicer to yourself xxxxxx