Don't fret over the ring thing. She may have worn it thinking she could "use"it if other guys tried to hit on her. Ironic, I know, but whatever it was, it was for her benifit while she was at the show. It was't to make any statement to you.
If she is a serial cheater, it may not stop until she seeks help from a professional who can get to the root of the cause. If she refuses, then no matter how great you are, there's always that chance she'll pursue another A.
When this A has ended, she may want you for her rebound relationship.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!
