How can I make my boyfriend trust me ?

So my bf is in the army n is stationed in Alaska and he thinks I'm cheating and he says it's hard to trust me he says this b.c I hang out with more guys than girls n b.c he said on fbook I sent this guy a message saying I love you baby which I'm confused about n now he won't make time to call or video call me n he doesn't call me babe or say ily any more.... I'm so lost plz help what should I do for him to trust me