Keep cool Mike...stay "dim"! Don't let her lure you back in to an old pattern that has not worked out for you.She must really believe she has you "under control" with her manipulative behavior.She needs some time to really feel the consequences of her behavior and to value you and the marriage above all else.
Encourage her to get some individual therapy from a "marriage oriented" therapist.
Mike,one thing I don't understand is how, (if she is so overwhelmed with school,the kids,the housework etc,)in the world does she find the time for "affairs"?
How long have you two been maried? Is there a significant age difference between the two of you or cultural/ethnic differences?
You continue to have the upper hand don't jump back in to the frying pan prior to her making some changes. Do you have a counselor, Mike.
It sounds like this marriage has a good chance of making it,but you both need some help to set it on the right course.