Hi Jeredc. I see you're new, so welcome.
As someone who has cheated on partners in the past, I can definitely say that guilt can keep a person from continuing a relationship. I know it probably sounds odd or unfair, given that she is the cheater and not the cheatee, but I remember when I had a long distance relationship and I cheated on my boyfriend quite a few times, and each time I felt so bad for it that the only thing I could think of to fix the situation was to break up with him and save him the grief of having to deal with me.
Hope that helps. Good luck with everything.