The reasons she has told you about why she had the affairs, I know becasue they sound way too familiar, are reasons to justify her behaviour, not the reason why she had them. It is a little difficult to explain, I do not think she has dealth with why because she still seems to be "blaming you" for not fulfilling something, so she had affairs...
Now she just wants to stay at home with the kids?
Torn, I will be honest..something is just not right here. Now it is completely possible that she has decided to change her ways and stay at home with the kids, but it is more likely guilt from the way she has treated you. Eventually she will either become depressed, or lash out as she has not come to the root of her issue(s). She will blame you and the cycle will continue all over again.
I know you guys are in MC, but have you considered asking her if she would like to see her own C? I know you would like her to talk about these things with you, but the probability of that is pretty low.
Has she been open with her feelings and emotions in the past, or is she one to bottle them up and let them stew? I never talked to my H, always said everything was fine, ect, ect.
Torn I guess the one thing that is the most important is:
What do YOU want to do? If you feel that you can not continue in this marriage, you must voice this to your wife. If you want to stay, voice this as well, but this is purely your choice. Tell her if you choose to stay this time, she will have to help you save the marriage. You may need to put some restrictions on her. Where she is, having her call when she is on her way home from work, ect. Whatever you need to help you through this. If she does not want to, I would seriously re consider staying.
Discuss these things in your MC session if you feel it is more productive there.
I don't know what else to say, except good luck, stay strong and do what you think is best for you.