I want out.

I'm confused my BF is what I would consider bipolar 1 minute he's as sweet as candy the next he's as mean as possible. Lately we've argued because in the past 5 years I've gained 20-25 pounds. I've yoyoed the weight but lately I'm at the heaviest ever And he's been pushing me to lose the weight or he'd leave me. His words hurt and only make me upset. He told me that he would cheat on me if I didn't lose weight and if/when I do lose it he wants to fuck me a few times before I leave him for another guy. He's also made me pay for Things like food and drinks because if I was a 10/10 he wouldn't mind but since I'm not I need to start paying for myself and occasionally for him too. I needed to vent sorry.