FIRST, THANK YOU FOR YOUR SERVICE.
it must be hard to work in a stressful place and be far away from family at the same time.
sounds like you dont have any proof,, not saying your wrong,, but you got no proof. when you start throwing acusations around without proof it does you no good, 1. she can deny it, 2. if she is innocent then it will actually push her into cheating. like my mom once told me,, you either trust them or you dont. it dont matter if shes innocent or guilty,,your fault or not,, if you dont trust her you shouldnt be with her (i understand the time and family makes this a little more complicated but the ground rule still applies) ... for example if i trust my girlfriend and she went out to the club with her friends and came home 2 hours late, i would worry that she is ok and not that she is cheating on me. but if i didn't trust her then it would be the opposite.
if your gut is really telling you not to trust her, then hire joey greco! (cheaters) Like mp123 said,, you need to worry about lawyers, and child custody, and your assets, spouse support etc. get a PI and build a case,, if he sees her smoking weed around your kid then you need that for court and custody ,child support etc. EVEN IF SHE IS GUILTY DONT LET HER KNOW!! JUST LET THE PI BUILD EVIDENCE AGAINST HER,, AND JUST ACT LIKE EVERYTHING IS COOL AND THEN SERVE HER DIVORCE PAPERS WHEN YOU GETS HOME! (you dont have to be hostile about it,, long distance relationships are hard no matter what the circumstances,, it may be best for your kid to be civil and not fight,, but make sure you get a lawyer thats a f-cking heartless killer!)
and worse case if she is cheating, then on the bright side you got a free pass to drink beers with your buddies and party with strippers when you get home.
while you play action man 6000 miles away.
you need to learn what respect is,, pro tip: you can't "google it"