What she says doesn't matter. What you believe and want is all you should consider right now.
Is cheating a dealbreaker for you? Personally, I think it's the fact she lied about it for so long that is the true dealbreaker.
What she did, though you may not realize it, is this:
By never confessing her cheating she took away *your choice* to stay with someone like this. If she had confessed and truly made an effort to make amends, and to commit to fixing whatever drove her to cheat, then you might have something to rebuild your trust upon.
You have none of this. She didn't just cheat--multiple times--she disrespected herself, you and your relationship by breaking your trust. Not just once, but twice by hiding the truth from you.
I would never want to be with someone like this. I would never, ever want to have children with someone who could do this. So, it all depends on your own values. Is integrity important to you? Do you believe in living by your word and owning responsibility for mistakes? She doesn't. Remember when all is said and done she had several choices she could have made differently:
- she could have told you she was feeling unsatisfied in your relationship
- she could have told you she was feeling an urge for sex with someone else and try to explore why this might be
- she could have broken up with you, set *you* free to find love elsewhere, instead of having her cake and eating it too
- she could have confessed to you after her affair and gave *you* the choice whether to fix things or break up
None of this make her evil, but it might make you very incompatible at a very fundamental level. And, as you can see, there are many women out there who would make different choices.
Good luck in your decision.