There are a couple of things that you can try if you have trust issues with your spouse. You can keep an eye on things that he is doing and then if you see something that does not seem right, you then confront him.
that's a very big sign something is going on. if you have access to your bill online, check out who he's been calling or texting. he can't delete that stuff. also, see about putting a tracker or something on his phone. I don't know if it's possible but it sounds like a great idea.