I read that you want to confront her...to tell her what she is doing and how it is wrong, etc. The truth thought is that it will be futile because she doesn't care. You cant logic or reason with her.
Read some of sandi2's posts. She was the wayward. Remember, women are attracted to "power." Not unhealthy power, but confidence, someone who knows who they are. Be careful not to come across as needy and pleading. Being nice to her won't change anything. There's also a good chance she wants to keep you available in the background as a Plan B.
me: 46 h: 49 m: 24 T: 27 DD1:20 DD2:17 DS:12 BD1: PA for 2 yrs 08/2016 BD2: OW is one of my closest friends 12/2016 BD3: H wants a D 11/2019 Now: He is in the same house, but has filed for divorce.