You either trust him or you don't.
If you don't trust him it really doesn't matter if he is cheating or not. Dump him! A marriage without trust is worthless.
In most instances when someone suspects their mate is cheating on them they're correct. (Unless they are just plain paranoid with everyone they get involved with).
Make sure you're not (looking) to distrust him in order to justify your own desire to cheat while he is away. Too often people will say, "I have no idea what he/she is doing. For all I know they're with someone else at this moment."
Sometimes people will practice what I call (self-defense cheating) to 'protect' themselves mentally from being hurt as much if they were to find out their mate cheated. It's a crazy head game! If they learn their mate cheated they have the small satisfaction of knowing (they) also cheated too! "While you were doing your dirt I was doing mine!" It's insane but it happens more than you'd think.