I need an advice plz?

Well this is kinda a long story, Im a friend with a couple, she lives 2000 miles away from where he lives, im a good friend of both, i live in the same city as the guy, and somehow they've putted me in the middle, i don't want to be in this position but i also know that if im not in there, they would probably end up appart cause im the only reliable person she haves "near" to his boyfriend, and she feels the need of keep asking me once in a while if he's being respectfull of the relationship, i really can't take a side, and im sure he loves her and the other way around, but its becoming hard for me, he and i went to some bars this past weekend and he ended drunk dancing with a girl at 5 am, i know he was wasted so i can't put the whole blame on him, in over a year i've seen him caring a lot about his gf, he bought her plain tickets to be with her during new years eve, and he have flown to see her a couple of times this year and the other way araund, thats something that tells me . . .