How to get over it

My boyfriend is in the military and we have been in a long distance relationship for the past year and a half. I had never even thought about the chance that he might fool around with other people but when i went there to visit him i saw some messages in his phone to his guy friend talking very explicitly about a girl that works at the gym he goes to. I asked him about it and he said it was just jokes and that all men do it when they talk to their other guy friends. I dont think he was cheating on me but i cant get over what he was saying about this girl. Do all men do this? How do i get over it?