Alright so I am 18 and my friend is away at bootcamp for the marines, he will be back in like a month and a half, but i talk to his girlfriend occasionally and we have been hanging out a lot (going for runs, swimming, movies). He has been dating her for like 2 years like on and off, he has cheated on her a couple times but she has no clue. Like i feel that he doesnt treat her right and she doesnt know it, but since ive been hanging out with her im falling for her or scratch that, i have fallen for her, she seems like the perfect girlfriend. What do i do? I havent made a move yet, how do i tell her, should i tell her? She doesnt seem like the girl that would cheat on him though, she loves him too much.