Gosh, you are awfully hard on yourself. You were thrust into a parenting role that wasn’t yours to take and you ponied up until you were 18, that is very admirable in my book. We all feel like we are selfish jerks at our core, sometimes. I think the key for you is forgiving yourself. Maybe somewhere you don’t believe that you deserve to be happy.
You had a rough time of it, I don’t think you did anything wrong. Go to counseling, work through your issues, work on loving yourself. You can’t change just for this man but, until you learn to love yourself, how can you love anyone else?? You are worthy of every good thing, be as kind to yourself as you would be to a total stranger.