I hate my mom's new boyfriend how do I break them up?

I don't like him at all. I mean he is always at our house and he was with my mom at my dance competition which made me mad since I was only expecting her to come. Plus he is at our house every other day for dinner. The other day I snapped at him and my mom took his side. I was mad at my mom about something else then he tried to talk to me saying he knew how teenage girls were so I told him that how would he know his daughter is way in Phoenix and doesn't even know him. I was right and she took his side! What is her problem? I want them to break up. I mean for years it's always been just me and her, and that's how it always should be. SUre she seems happy but everyone knows that guys are just temporary happiness and they will break up with you and give you heartache. What is a good way to break them up?