Women are emotional vindictive creatures. They like others to be on their side and love gossip. Her posting this not only fuels her need for attention but her hive mentality as all of her friends "like" it, it will make her feel more important. In the old times they used to gossip by phone. Now they use facebook. Same shit as 50 years ago.

My advice? Find some new ass. Different social circle. Then post happy photos about how much she enjoys you. Best revenge.