i don't know what to do

I'm 16 turning 17 and my boyfriend 15 turning 16 (yes ik we're both really young and i admit we were both stupid) we've been together for about 3 years a but on and off for about another year. We met when we were both 12 and started having sex when i was 14 and he was 13. (He's 9 months younger than me but we are in the same year) i got pregnant in 2024 and found out when i was 8months pregnant since i wasn't showing any signs. I have a very long history with mental health and have been struggling with diagnosed depression for about 5 ish years which may contribute to as to why him and i are still together since i have attached myself to him as some sort of regulator.

Him and i have a son together (1 years old) and we currently live together but he has a past of cheating and i decided to forgive him for it and honestly he was doing fine up until 2-3 months ago when i found out that he's been chatting with some people online. Which has had me thinking about leaving him but im not sure how to since i live with his family and my family is toxic and very unhelpful with my son while i attend school. My MIL has been helping us raise my son while him and i are at school and studying and hes usually at daycare from 8-5. At my boyfriends house its a 15 minute walk from his to daycare but from my house it's an hour trip since i don't have my license. Usually its my MIL who drops him off cus my bf and i have to be at skl but at my house i'll have to be the one to pick him up and drop him off. Im just not sure how to breakup with him or handle our kid.