Her friends have a trip planned, and her ex is going. You asked her not to go, but she reassured you. She wants nothing to do with him. You text her afterwards, asking how it went..
She didn't want to cheat on you with her best guy friend and she didn't want to get pregnant either so she figured this was fine. It didn't go in her so that's ok right?
She told you it was just drunk sex with a friend. She didn't tell you about the passionate make out session after he ejaculated inside her twice, though.