My DD is 22 and was with a guy for 4 years, up until last November. It was her first "serious" relationship. She moved out November and met her current bf not long afterwards. They are now expecting a baby boy together next month. DD's ex met a new girl, 4 years younger than my DD, and now they're expecting a baby together sometime next year. So basically, its like both are having rebound babies.
The problem: Ever since DD found out about this, she's done nothing but complain and talk badly about this girl she doesn't know. She comes over at least 4-6 times a week and it always comes to this subject. ALWAYS. What did I do? I let her vent. She's pregnant, I try to take into account her hormones. But tonight, I just couldn't handle it for the 100th time. She started in again and I finally said "Listen, you just need to STFU. I taught you to treat people the way you would want to be treated and I doubt you'd want C****** to talk this way about you." She got upset and left.
Before anyone pounces on me: I love my DD. Very much. But I didn't teach her to act this way, especially when she's in no position to judge. I had a bf I was with for years until we had a mutual break up. How did I take it? I let it go and went on with life. I can't stand when women dwell and insult their exes constantly and my DD is no exception.