What really matters here is If you can answer yes to these questions, then at least you know you’re with a guy who makes an effort to never exclude you or make you feel less than his priority.If the answer to any of those is no, then you may have a right to be concerned about his female friendships (and vice versa, if you’re the one with guy friends and don’t do him the same courtesy). To be frank, this is an issue for which I would never offer a concrete prescription because I just know that so many couples vary wildly in their rules for platonic friendships.
Basically, if you can both drink ten shots of whiskey and still not want to tear each other’s clothes off, you can safely be friends.
People need to bond with people in and outside of their gender and if it skews too heavily in one direction, it's a red flag.
EDIT: One thing I've encountered in dating is that women tend to be more supportive of relationships than men are.
If you were asked what you thought were your opposite sex best friend's best features were, you could probably come up with a whole list.
Your consciousness of your friend's attractiveness is the foundation for developing feelings.