i'll break this down simply for you: how many friends do you have? girl or guy? do you only have one of each gender? do you lose all your guy friends when you start dating, because the only reason they're your friend is the potential to vag-dive? if the answer is yes, you're an asshole.

i mean, this applies to all gender relationships. do lesbians have to not have friends who are girls? what about gay men? and bisexuals have to live in a tiny little bubble of aloneness? healthy humans have multiple social interactions with a variety of gender groups. you might have a bff who's a girl and be a het girl who's married to your other bff, but that doesn't mean you can't have other friends who are both guys and girls.

the better question is; why wouldn't you want to be friends with some other guy? friends =/= fucking. a lot of people have platonic friends. if you can't manage that, the problem is you, not the idea of having platonic friends.