How do I stop feeling lonely in my relationship?

Im 21 and I love my boyfriend we've been going out for 3 years. a few months ago he joined the sheriffs department and was gone at training for well over a month. We had been having troubles but the break from eachother made us realize how much we mean to eachother. But as soon as he came back he left again. I only had him and no other real friends. He started his cop work but it's far away in another city. He lives out there 5 days a week I only see him a couple hours 1 day week and it's hurting me. It doesn't help that when he sees me he's a complete Jerk for no reason and says it's because of the stress of work. I find myself growing Attracted to other guys and I don't know why. I just feel so alone and instead of having a partner to lean on I'm all by myself. I don't war to feel this way. What do I do .