Good question! 🙂
First of all, do not confront [b]her[/b]. She is trying to interfere in your relationship. If you give her any attention it validates her place in your life. So your best bet is to ignore her.
Second, ask your boyfriend what he thinks of all the Facebook posts from her. Listen to him. If his behavior hasn’t given you any reason to distrust him, then don’t.
What is important is the communication and intimacy between you and your boyfriend. In your future there will be other challenges from people who want to intrude — they may be your exes, they may be a future in-law or relative, they may be someone from work. You will always win when you ignore outside forces and strengthen your relationship from within.
I hope that helps! Good luck. 😀