Paul.... if I am reading your sitch right and your partner has cheated on you four times - do I have this correct? I have to seriously (but I hope compassionately) question why you want to be with someone who has hurt you so often. One or two mistakes happen... but more than that? it shows a reckless abandonment of wellbeing for not just you, but herself as well; I think it shows someone who is fighting a lot of personal demons, for a start, sexually; and also a very poor choice in men in general - perhaps Paul, you really ARE just "too good for her".
and perhaps deep within herself, she beleives that as well...
When you're down to nothing, God is up to something.
