Most Helpful Guy
Depends what you define cheating as. If it's an ongoing thing and he's doing it for long enough, you probably will eventually find out. If it's only a short hook up when he's away, you probably won't.
How will you know? Trust me, you'll know. Now there's no point in worrying about it, you've got to trust him. If he ends up cheating, then deal with it then.
Most Helpful Girl
Here's the tricky part of this question... if you ever begin doubting your boyfriend, then it's all over. Same if he doubts you.