It sounds like you need to pull back a little bit. There is no need to be having these conversations with her. She see's that she has you anytime she wants you. She is flat out lying to you right now. My wife did the same thing. He is not my boyfriend bla bla bla. Then what the heck do you call the guy you are talking about having sex with. I found out the hard way that these discussion do no good. It doesn't matter what you call him, he is the OM and he is a problem.
The OM is never the problem ... a POS/ rash .. sure .. not the root cause of the true problem ... if your M was strong and good there never would be an OM right?
Once you arrive to the place where you realize the OM is purely the band-aide for the cancer of hurt/pain the M had/has ... and there is nothing you can do about it the better you will be. The A will run its course, but if you do not become the better option .... no chance the WW will even look in your direction.
You are the Alpha ... do not allow any OM to make you feel nor act otherwise.