Questions to the marines, only marines?

My boyfriend of two years is going into the marines eventually, and I've heard things about marines and what they do while away. I'm worried ... So please answer these quesions... What is a marines life like while away from family/friends and girlfriends? What do you do for fun, and are there girls around? Also... What motivates many of them to cheat? I don't want to catagorize but it's hard... Oh and if your a marine, have you cheated and what made you? Thank you