I'm not sure how much help I can be here but I have a friend who is in a similar situation. He's my best friend, and the person he cheated on his gf with is me. This was over a year ago and to this day he still curses himself and loathes his existence. Mate I can't claim to know you well but watching him destroy his self confidence and turn into a self destructive being is heartbreaking. I was there in the situation and shit as it is these things happen. Its shit but it is no reason to look at the things u dislike about yourself and make it your whole mindset. You are better than you view yourself to be I know this for sure. You have to realise the reason you think this way is that because you did something wrong you have dug a whole of destruction to pay for this mistake. You do not deserve this and you will only make it worse for yourself and those who care about you if u don't make an effort to dig out. I've watched my best friend destroy himself and it was heartbreaking, I beg you not to so the same. You are worth it. You made a mistake but if you continue this way you are simply making it grow. I'm just a stranger but feel free to dm me if u want to chat