Most of the answers to this request echo my own sentiments on the subject. If he's packing to facilitate some extra-curricular activities while he's away, he's got no business being in a relationship and you need to kick his ass to the curb. He doesn't care about you or how he's making you feel, he only cares about getting a strange piece in a strange town. Dump him and find someone you can trust (yes, they do exist).

One thing I have to disagree with though...many of the responders suggested poking holes in the condoms as an act of vengence. While it might be tempting, and momentarily gratifying, DO NOT DO THIS! It won't just be him you affect; in fact he most likely won't stick around long enough to see the damage it causes. You could leave some unsuspecting girl (much like yourself) with an STD or unwanted pregnancy. Trying to get back at him could cost someone their dreams, health, even life. No one deserves that.