Opinions are just opinions, it all depends on what she hates more, being cheated or the uncertainty from divorce. As far as the function of marriage goes(love, practical matter and give a stable home for their child), she gets out very little at this point. Maybe little bit of financial benefits, that's it.
Is she willing to trade uncertainty for another chance for herself, only she can answer that question. And of cause whatever she feel most confortable is the best answer for her.