cheating! (ADVICE, WHAT DO I DO?)

hi, so I have been with my bf for 6 years today. we have a 3 year old son together and a bought house. we're settled a little and we have been together our whole lives. I'm 22 and he is 24. Our relationship has been rocky. I feel underappreciated and he spends most of his time on his video games. he works 5 days a week and I work 3. this however, is interpretation for him to do nothing and think I should do everything for him. most of the time I feel like a single mum. it breaks my heart. there's just no romance. I have to instigate sex all the time, ask him to make an effort. if we're out he will completely ignore me and don't get me started on him asking me to dance. I've never danced with him at any point in 6 years. anyway I have a best friend of 5 years. he's a very nice looking guy and we get on so well. anyway we had a catch up at a bar. a few drinks lead to a lot of drink and we were laughing and he pulls me up to dance and were having such fun. then he kissed me. I should have stopped it there, but I didn't. we went on to have sex that night. in the morning we just lay there. I know what I did was wrong. I hate myself for that. his girlfriend found out by looking through his phone the next day and she told my partner. he forgave me, but what happened is making me think I want to leave him. and stay on my own with my son. he got physically violent after finding out. I know I did wrong, but he shouldn't have triedc to choke me.