So you emailed OW, told her that if she just tells you that she's had contact with WH in the past few months that he would be hers, and you wonder if she'll tell you the truth? You should have just gone to the courthouse and filed D papers since it appears that you want the M to be over. You threw a bucket of blood into shark infested water, and you wonder if the shark will bite?
I get the desperation, I really do. But telling the OW that she can have your WH if she tells you they've had contact almost guarantees that you'll not get the truth, and you also will forever wonder if she lied about the continued contact in order to get your WH. It's a no win situation, unfortunately you can't take it back now.