My friend was dating this girl for 3 years and even proposed to her. They were supposed to get married in a year.

Well the girl comes clean and tells my friend that she kissed a guy from work while hanging out with friends. They didn’t break up at first, but of course my friend was hurt and didn’t want the girl to hang out with this work friend anymore.

Well THEN the girl comes to my friend about a week later and says that she wants their relationship to be open. My friend says “I don’t want you dating him if you’re going to be with me.”

So the girl says that that’s a dealbreaker....

She’s known this guy for like a month and a half! She was ENGAGED and just got a HOUSE with my friend!!! Their relationship was great until then!! My friend often talked about how great everything was! They never even fought! I’m just so mad!!

What should I do to help my friend???? (I really wanna punch her ex but I know better)