I'm so sorry to hear this....that would hurt so bad! Especially when he's told you before he wasn't looking. Have you printed off what you have to confront him with it? Or perhaps pull it up on the computer screen....leave it there and put a post-it-note on the screen that says...."we need to talk".
IMPO....you do need to confront him with "proof". It's going to be awfully hard for him to deny his actions now. Now, maybe he hasn't actually seen anyone yet....but the "intent" from his email says he wants to. You need to let him know YOU know about this.....and that there are consequences for what he's choosing to do.
