My friends used to always say DH (who was DB then) was probably cheating on me and there was no way I would ever know and lots of other negative things. I admit I let them get into my head once in a while, but overall, I knew what I thought was most important, and I didn't think he would cheat, so I had faith in that, and he had the same in me. We both got a bit jealous at times, it's hard not to be when you don't get to see each other, yet maybe you are able to spend time with a close friend of the opposite sex or whatever. LDRs are tough, but remember, he has to put just as much trust in you as you put into him. When my friends would ask how I knew he wasn't cheating, I would ask them how he knew I wasn't cheating!
Of course I had fearful thoughts from time to time, like what if it wouldn't work out after I moved over here, and he was terrified (and still is sometimes) that I might not like it here or be too homesick and want to move back, but in the end, it was worth taking the plunge. If you let negative thoughts talk you out of a good thing, you might regret it later on, but that is what you have to decide for yourself. Good luck!!!