Just to be clear, theoden and Starsky's approaches are in regard to the situation AFTER the cheating WAW has shown a willingness to work on their marriage again, correct?
If the WAW is still very much engaged in the A with the OM, and has made no indication to reconcile, then I would think "standing ground" would simply drive her away faster (according to DB principles), no?
M: 15 years BD: 6/25/14 EA/PA: starts 5/14/14 11/30/14 - A ends 5/15/15 - D is finalized. 11/28/15 - Start of new LTR with a wonderful woman (and still going strong)!