How do I tell my mom I’m dating?

So I’ve been with this guy over a year, we broke up for a few months because he couldn’t decide what relationship he wanted but know he knows he wants to be my boyfriend. He is starting his last year of masters and is honestly the best man I’ve met. He struggles with depression, which results in him saying some mean things sometimes, but he literally is the most sensitive soul.

When we had be together for 7 months we were not official, and we had a huge fight in which I told my mom everything, including his lack of wanting a relationship. She immediately hated him and wanted me to never see him again. I have no idea how to tell her we are, not only together, but planning to get married in a few years. She has an extremely controlling personality and constantly demands to know what you are doing at every moment and has the mindset of “Make your own decisions, as long as I approve”

My boyfriend absolutely hates her because she constantly fat shames me and doesn’t like when I show my body off. I am 19 and want to wear tight clothes and bikinis and low cut tops, which my boyfriend encourages.

I have no idea what to do, help?

I’m a junior in college btw, I’m 19, he’s 23