It's wrong to cheat with your friends' partners.
Carmen has just met her boyfriend's best friend Danny at a party.
Carmen wants to have dinner with Danny.
Carmen invites Danny over to have dinner with her and her boyfriend.
Carmen invites Danny on a dinner date when her boyfriend goes out of town.
Carmen's boyfriend enjoys spending time with his girlfriend and his best friend.
When Carmen's boyfriend gets back into town he beats up his friend and breaks up with Carmen.