Is my boyfriend gay?

ok my boyfriend he a type of person hu thinks he is hard and he dresses in trakkies and always wear hats bt he always goes behind all he's boy mates and starts humpin them bt all he mates think he does it for a laugh bt nw it been bwt 2 months nw tht he does and the other thing he always gets he private parts out to them bt its nt . bt ive had ppl min up 2 me sayin is he gay he is only 15 ive been with him for 3 months so do u think he is gay plz plz help