Praying for you my man. I spent 5 years working long distance from my wife and kids, and it's tough for a number of reasons. The hardest is the being lonely.... I started hanging out with one of my employees, and living the party life with him, drinking every night. Not a good thing for sure.
Thing is, with things going the way you have talked about in your posts, I believe your wife would have told you about a past affair. Things are going much better for you, and this is a major road bump causing you to trigger.
On your service- My BIL spent a tour as a medic over there.... From his stories, if you got medals, dude, you deserve them. There are guys you fought with that I'm sure thank their lucky stars every day that you were there.
Not sure how you deal with the triggers, but this sounds like the mother "f"er of them, and with not turning to the alcohol, it seems harder to face.
Wishing you strength, and peace.