You shouldn't sleep with someone in a serious relationship.
Brenda is at the club when her married friend James asks her to come home with him and have sex.
Brenda wants to respond to the offer of sex.
Brenda tells James that there's no way she's going to let him cheat on his spouse.
Brenda tells James that it sounds like a good idea, and they should probably leave soon.
James' wife later finds out and thanks Brenda for saying no and dumps James but keeps Brenda as a friend.
James' wife later finds out about their affair and breaks off her relationship with James and her friendship with Brenda.