Sorry but why are you not more mad at your bf???? Why are you messing around this person who clearly has a lot of shit to deal with. It’s your bf that cheated, be mad at him first, the other guy next. Outing this person to their family is dangerous tbh, it’s not a mature thing to do and you’re only doing it to “get back” at someone. It won’t help you and it certainly won’t make you a good person.