I don't know if your boyfriend is okay, but I do know this is not typical behavior. Have you asked him about it? Maybe he has a reason for doing this. You don't say how old you both are, and that could be a factor.
I would definitely ask him why he runs out like that, if he is having a physical issue or whether it is nerves or something else. If he has a need to urinate that often, perhaps he has a urinary tract infection or something. I would say if it is a physical need, he should be checked out by a health care provider just to be sure he doesn't have some sort of infection or other issue going on.
Thanks for writing.