- No, don't hookup with him. Don't ruin your sister's relationship.
- hookup with him without letting your sister know.
- Ask him to breakup with your sister first.
- just tell your sister that you would like to hookup with her boyfriend and let her decide.
Most Helpful Guy
Now flip the situation. You have a boyfriend your sister is attracted to. Would it be okay if she has sex with him, even if you might never find out? There's no such thing as "never find out". Everyone finds out, eventually.
Most Helpful Girl
Um no. I was given the same opportunity except my sister is married to him and they have kids. He tried having sex with me while she was in the hospital having their 3rd child and I was babysitting at their house. This was over 2 years ago and I'm over it but I'd never do anything like that. There's too many men in this world to go behind your sisters back and sleep with her boyfriend. Stop flirting with him. If you decide to pursue sleeping with him or something. There's no scenario where that turns out well. You'd hurt your relationship with your sister and family and it's not worth it over some d*ck