I don't think it's the guys you are worried about. I do believe it is her. She betrayed your trust and now you are trying to find ways to make yourself comfortable with her being around other males.

Also, how old are you? Just out of curiousity because I get the impression that you aren't very old, but I could be wrong. If you are younger, I'd say break off the relationship because it's not worth the stress, and if you are older go to counceling with her and work it out before your jealousy destroys the relationship.

You sound very insecure. Is she a slapper or are you unable to satisfy here sexually?

Okay I seem to have lost my train of thought but I'll get back to that.
Now this may seem a very far-fetched, revolutionary new concept; but you could just TRUST her.
Or better yet attach a small tracking device to her leg. Also, if economically practical, just buy a 10-gauge titanium chain about 25 feet (or however long the distance is from the kitchen to the bedroom) and go from there. Also may I suggest a midieval chastity belt made out of iron with a masterlock on it, and invest in one of those electronic shock dog-collars but programmed to go off whenever she looks at another guy, girl or road sign (they can be pretty wily.)
Another option would be to simply acquire a private eye/hitman to follow her around wherever she goes, then acquire ANOTHER private eye/hitman to keep an eye on the first one; make sure he doesn't try anything. They can be even craftier than the signposts. Just remember to explain, if they're foreigners that the title doesn't connote keeping an actual eye on her actual privates to avoid future confusion/unemployment on their part.
Peace.

you're my hero

u should trust her!!!!!!

Yes, Mandy is right. Trust her, damn it! You will drive her away and she will be spending all her time doing "Hoework" and you'll never see her again.