If this is a sign, please kill me now...

Lets just start out by saying yes I did cheat by sending nudes to a girl a few months ago and yes I did tell a girl I want in a relationship a few weeks ago, yes I am a piece of shit and yes, most if not all of my relationship issues are my fault and in the end I wouldn't blame her if she cheated on me....I think what hurts the most is slowly realizing the abusive pattern we've fallen into....we fight, make up, things get better for a bit and then something(usually me) triggers another fight....I want the cycle to stop but there are only two ways to stop it and one of them ends with two broken hearts.....how do I fix myself, how do I stop myself from being a horrible person.....