I know you understand, and I really like your advise because your going through something similar (although I have no proof of affair which for me would make things black and white and much easier).
It's funny cause when I read your sitch, I thought no brainer. She needs to take him for what he's worth, she deserves better. When it's me I think I'm to blame, and I drove my husband to this,
Regardless, husband made choice to leave. I don't know why I am being weak and enabling this behavior. By doing this, I am a character that I don't like or respect. I have also greatly devalued myself.
I need to commit this saying a relative of mine says to her bf...."I love you, but I love me more"
Me: 42 H: 43 Twins age 5 Physically Separated 7/2015