I was told by my live-in boyfriend to move out. (But I'm the one who bought this apartment though?)

On my day off from work, after spending a relaxed time playing with friends and returning to my apartment, I found my live-in boyfriend had brought another woman inside. And they were in the middle of enjoying themselves on the bed, no less. What? We can break up, right? That's it—I'll wrap her up with a bow and give her to his affair partner.