My wife denied she was having an affair with a co-worker too...but I confronted her with the data I had and she had no other option but to admit it. The problem is the quality of the data you have and how convincing it is to you and her. In my case, I hid a voice actuated recorder in her vehicle and taped conversations during her lunch breaks that she had with her co-worker. I found out everything and then confronted her with the knowledge I had, and of course she was in a state of denial. After I noticed I was getting no where, I played a segment of the tape for her and she began to talk. It was like pulling teeth for the next couple of months to get details and if it would not have been for the taped converstations, I would not have gotten this out in the open. To this date, I still do not know all the gory details of the affair, but I do know there was an intimate relationship. We are in counseling right now and making some progress but until this is completely out in the open, there is very little hope of recovering completely. As my MC has told us, that if she is not sincere in cooperating with my desire to have full disclosure of the extent of the affair and to stop all contact, especially if emotions are being shared, the risk will be that I will soon get tired of this and will leave her for good. He also mentioned that a divorce with minors and marital assets can be very painful, costly and regrettable. I think this has gotten her attention and now I am in verification mode to see if she is complying. As I have mentioned to her already, if I determine that there is contact going on, our relationship is over. In the meantime, I have been applying plan A to it's fullest and it has worked. She is paying attention to me and enjoying time together. However, since the other other man is single, I have the feeling that he is still being persistent despite the fact that she has ended the relationship. I expect her to have the discipline to hold her end of the bargain irregardless of the circumstances.
I hope this helps.