Veteran speaking here.
First Welcome. I hate that these circumstances have brought you here, however you are a bit ahead of the game, because you have an opportunity to catch this early. Your relationship sounds like it was primed for an A. Loss of intimacy, stress of life etc.
The first thing I would encourage you to do IS NOT CONFRONT until you have proof. Cheaters are liars, and even though your wife is your wife, and she is special and unique, if she is cheating she will follow the same BS that all cheaters do.
Example - I knew in my gut my H was up to no good, figured he was either doing drugs or having an A. The drugs I suspected because his personality changes were so extreme. The A I suspected because he used any and every excuse in the world to be out of town, and not spend time with his family. Plus weight loss, changes to hair, new clothes, etc. However I approached him multiple times when he seemed aloof, sad, or stressed, and tried to get him to talk, and he was going to his grave with his secrets. It took me 6 months to get the proof I needed. If I had kept my mouth shut about an A, I really think I would have caught a slip up sooner.
I would suggest you do a few things first for yourself.
1. See a lawyer, find out what your rights are, and what her obligations are, should she completely loose her shit, and decide to D, or leave. I know more than one woman who abandoned it all, including her kids.
2. Get a Keylogger on any electronic device you can, phone, computer, tablet etc.
3. Put a VAR (voice activated recorder) in her car.
4. Put a GPS on her car.
5. Keep your mouth shut for 48 hours after you do all this, I am willing to bet you will have your proof in that amount of time.
Decide for yourself if you want to work things out if you find out if she has cheated. Decide what you would need her to do, and what would be deal breakers, and have that stuff ready for when you confront.
If you confront prior to having the proof you need, you will be given a run around, question your sanity, and she will be tipped off that you suspect, and become much more careful.
Offer to detail her car this weekend, and pop the VAR and the GPS in it, while looking for a burner phone, she erased her emails already, which tells me she has a heads up, and may already be covering her tracks a bit better. Burner phones are very common for cheaters.
Listen this shit is hard, and scary, and it sucks. It's unfair, and maddeneing, but know this. No Matter What she says, you did not cause this, you are not to blame for it, and you do not deserve it. So when you do confront, demand the respect, honesty, transparency, and honor that we all deserve.
Keep reading, Keep posting.
(((and strength))))