I guess you are about 18, three months isn't very long even at that age, and especially after a year of dating. When I was 17 I got together with a girlfriend in the middle of July, left on a gap yah trip two weeks later, didn't come back till the end of August. Didn't make the slightest bit of difference and we remained together until Christmas. Last year (age 20-21) I spent a year working in France after a year and a half with my current girlfriend, though it was challenging there was never any question of breaking up, much less cheating.
Just get on with it and enjoy the time you have to yourself to go out with the girls or even put together your own girls' holiday.
Mind you, the American girls will swoon almost instantly at the British accent ... especially if they're lower-middle-class