Relationship

So I am 19 years old and I go to college. my mother is a old school type of parent who think college is number one. I’m in this relationship with this boy for almost a year and have way through our relationship he cheating and yes I stayed with him because he makes me happy and ways that people can’t see and I’m not talking about sex he is turning 19 this year but still has another year of high school to do so he doesn’t work all the time but he does work and get money. The thing is he lives in Chicago and I stay in Michigan and go to college here so when I was in school I would drive down there to see him not a lot but like 5 times over the whole school year. My problem is my last semester all my classes was great but one and failed and when I told my mom my boyfriend was in the car. She snapped and said he was the reason and said we couldn’t be together anymore. I feel like I’m 19 years old she shouldn’t be the one to say we are broken up and can’t be with each other anymore because I have to focus on school. But the thing is one it’s summer time and two tbh he was the one making sure I was doing my school work before I go out and do anything at all every damn day. I want to tell my mom but like I said she is old school parent and doesn’t like to listen to me and my problem she just yells and I have to say yes to everything if not she’s just gonna keep yelling. Please help I don’t know what to do.