L & C, His telling you that if you do this, then I will do this, is his way of twisting this into being able to blame you for his bad choices and decisions. It is pure manipulation and a way to force your hand into keeping his secret. If you are worried that you will be retaliated upon for exposing his affair, then there has to be some way to make an anonymous phone call to someone that would be able to spot some sort inappropriate action between the two of them. Do you have any friends that work or volunteer at the school?
What he's telling you is classic A talk and like ShockedOne said pure manipulation. You have to quit thinking about whatever is going to make him mad because he sure isn't considering your feelings.
By the way, he's likely lying to her as much as he's lying to you. The best thing I did was to have a heart to heart with OW but that was after months of different approaches that didnt' work. Does she have a spouse to expose to?
Bluestar- Hadn't checked this thread in awhile. The information I got from him initially was that they were separated. I just found out in the past 2 weeks that he caught them emailing before I knew about the affair. They fougth and she move out. I don't think that he knows everything though b/c if he did I can't understand why he wouldn't have contacted me.