I am so sorry. I can not even put into words the disdain I have for that thing interfering in your lives.
Honestly I would just tell him straight out he needs to wake up and the smell wench. Why after the years you spent together would you do things like that. You need to ask him why he does not think its odd that suddenly after being with this horrible woman that his stuff is missing. Ask him why he can not see that she is setting him up. Ask him how can he believe a woman who obviously has no morals over his wife. Tell him that these OW lie lie lie to get what is not theirs and sadly Hs fall for it. Tell him you are not even going to acknowledge anything else you are blamed for because he fails to aknowledge that OW is a liar. Tell him you are amazed he does not see it. Tell him you thought he was smarter than that, but obviously you were wrong just like you were wrong that he was a man with integrity. Then include that you are too busy with too much going on to engage in childish behavior. Say it all nicely, then walk away.
Honestly I don't know if you can do that as per DB rules. But man I do not think I could handle someone like that OW. There is no way. Something tells me she is a OW by trade. If she does not ask for forgivness soon the sows she reaps will be 10000 fold worse then what she dishes out.
