I was actually on the opposite side of this when evrythig went south with Adrian. ALL my friends - EVERY SINGLE ONE - took my (or "our, including Violet and Lana" as they saw it) side, and weren't very nice about it. This really upset me - I know Adrian was hurting too, and didn't need the blatant shunning on top of it. At one point i actually had to call some people out on it on FB, their comments on one status update got so mean spirited.
When my previous ex (before Violet and I got together) and I broke up, it was messy with friends. People I'd known twice as long or more than she had stopped talking to ME becuase she skewed their perceptions of the situation. Some mutual friends turned on her amid my protests. It took over a year to settle down, and some of those bonds never reconnected. Oddly, a very good mutual friend started dating her shortly after the breakup, and our friendship survived, and survived THEM breaking up, and survived Violet and I dating HIS ex at the same time (remember Anne?) whom MY ex that he was now seeing had set him up with, LMAO! And he is still close to her and to me/us - though NONE of us talk to Anne anymore, lol. Some friendships are made of stronger stuff I guess.