Lil said that most every rule a person has has a story behind it. You gotta learn your own lessons. Dating's like a hot stove; mom and dad can warn you about it all they want but you're not going to realize just what "hot" is til you reach out and touch it. AKA all the warnings in the world are nothing against the pain of real experience.
I guess I can't blame you for picking the devil you know, but you know. It's kind of fun to go for the devil you don't. Besides, don't let people treat you like crap. That includes you. See, isn't this fun? My original post was twice as long but I edited all the stories out.
Still working on that bit. My therapist and I have diverged a bit from our original discussions, because we came up with some good coping skills for bigger problems. (Existential risk, total political immorality, Neo-Luddism) But he's directed me to some interesting reading that indicates that a person can't have a healthy relationship without first loving themselves, and I don't think I ever had that to begin with. When I started working out I used self-loathing as my motivation (Still do somewhat, work in progress) but that doesn't work well, or for long.That includes you.