I've been with this girl for fur months an she has lost her virginity to me but after that we always seem to fight I just want to be with her an we just decided to take a break but the thing is I am leaving on vacation for a month an I seem to feel at the same time she is going to cheat on me she said she wouldn't but I just can't get it in my head that she's not

Its a waste of energy to think what other people will behave behind our back but you know what, SHE WILL CHEAT IF SHE WANTS TO. If she really end up doing the did, then its up to you to you if you want to stay with someone who's not worth of trust.But I guess you know what you deserve in your relationship.

Dating for months still means you're just dating. The sex thing I'm sure was mutually fun, but it can make you stupid. Sex in an early relationship will always needlessly mess up your perspective. Oh well, water under the bridge.

Your fears / insecurities about things going on in the world with other people is no one's problem but your own. She may cheat, she may not. And it will have NOTHING to do with your fears either way.

Fear, and insecurity, can ruin an otherwise good relationship, and its something YOU need to effectively deal with, not her.

Well, no offense, unless the guidelines of the break were explained at the time it was agreed upon, then it's not cheating as you are broken up. If they were agreed upon, all you can do is trust that she will keep her word. Keep in mind, breaks hardly ever work out in your favor as they are just a line to bring the break up around easier.

If you can't trust her, your relationship is like starting a fire in a house, it's sure to spread until it's all burnt down. You have 2 choices here, trust her and enjoy your vacation, or spend your entire vacation miserable wondering about who she is with and what she is doing. Personally, I don't let anyone ruin my vacation. I earned that relaxation and I'll be damned if anyone is going to ruin it for me!