That debate is something that many had, for some it led them to get back to their ex, for others it led to cut the ex out completely. The thing is, the whole debate is wrong per-say, because the question is the wrong one.
First you need to understand that the infidelity changes your whole life completely. It changes the person that you thought she was. You learned what she is capable of and that she is not the person you fell in love with.
When you extend that thought to your lifetime, then you need to ask yourself, if you want the person she is, to be a part of your life? Not the person you thought she was and where you already made that decision, no, it is now about the person you found out she actually is. That changes everything!
She didn’t care about you, didn’t love you like you loved her, didn’t care if her affair would end the marriage. That is her mindset. So instead of facing the debate that you currently have, you rather need to ask yourself, what kind of person do I want to spend my life with?
But first you need to accept, that she is who she is. It isn’t that she is a different person now, you just now found out who she truly is.
You are worth so much more than to be treated this way!