Did you tell her that she can have all of those things WITH YOU if she gives you a chance and if she is committed to working with you and helping you to get there? You are a great guy, too, you know. And, I'm sure you're more than capable of making her feel chosen and loved and special and validated.
And, how great can this guy really be? He's cheating on his wife and taking another man's wife. Just another wayward soul.
She's in dreamland about this wedding ceremony. It's like she needs some fairytale ending in order to make the choice to come back. It isn't authentic until you two do hard work and reach a higher connection and understanding. You have all kinds of trust to rebuild before participating in her fantasy wedding.
She needs therapy NOW. You both need MC NOW. She needs to quit the gym NOW and find a new one. And change her phone numbers and email address.
I am truly, truly disgusted too. Do you want a real woman or a little girl? She needs to "woman up" and fast.