I am so sorry to read about this and hear what you are going through I cannot imagine how you are feeling, its truly devastating.
I truly believe that our gut instints are usually right so if you are feeling like he is lying, most likely he is. Maybe he is not lying about what exactly you think he is but something is wrong. The fact that he won't give you her phone number is a huge red flag. If he hadnt been calling her or talking to her then he would pony up the number no problem, so its pretty clear that there is more than just emails going on. And to email someone other than YOU, his wife, the day after you got back from your wedding to say he missed her, is just wrong.
Make sure you follow your head on this one even if your heart is telling you something different. You deserve the truth and only once you have the truth will you be able to decide how you want to proceed. HE should be willing to give you everything you want right now if he really wants to work on things. *hugs*