yeah not suprising she is going Monster right now ... she really has no back up plan as I think everyone can realizse OM is most likely not going to disrupt his family for an A nor a OW ... this really will eat at your OW as she questions the risk/reward factors as the risk is now escalating.
As far as the $ $... my wife made more and had more in the 401k ... like you I felt that was hers, but then I realized .. we were building a life together, doing what needed to be done, where I lacked financially I more than made up for what I did outside of work. But the big thing ... the kids, should they have less while with me due to W's actions? No .... she made her choice and those choices come with consequences. Do not just give her those things .. the L will agree, after 21 years of marriage all that is just as much yours as it is hers.
Sorry you also had a tough weekend .. hang in there, looks like you handled things well and W is starting to crack under the pressure.