I am sick of all of my mum's new boyfriends?

She's always dating different men all the time, and it's really annoying. She expects me to be nice to them all, and spend time with them all. I've sick of it. I don't see why she just can't be without a man. She's 55, and whenever one breaks up with her, she jumps onto the computer to look for a new man. She has another one over now, and i have to go and sit at the table and have dinner with them. He's staying the night too, which I hate. They won't stop talking either, and he keeps asking questions about me. Things like "What is Lucinda studying at school?" "What hobbies does Lucinda have?" I seriously think he should mind his own business! Why does he care anyways? He lives on a boat too, because his wife left him. I think my mother should go and live on the boat with him! How can I make him go back to his boat...?