Would it be wrong to date my cousins ex

Would be we wrong to date my cousins ex. (they have a kid together) My cousin does not get along with her ex, and I'm not close with my cousin. He came to the door, and I answered because I'm staying with her for a few months. Omg is he hot, and he's so funny.

My cousin thinks he's an annoying, ergocentic person. She also said she does not care what he does, or who he dates, but she would be beyond pissed if we are even friends.

He's so sexy, and he invited me out!!! What should I do. He seem like a really nice