Is it normal not to know to make male friends?

Well, I'd say you make male friends in the same way you make female friends. However, lots of guys prefer hanging out with women. As for me, my best friend is female.

Maybe try to hang out with a bunch of guys more often? Ask your male colleagues to hang out after work once in a while.

Also, you shouldn't feel guilty about being in a relationship while having female friends. If your girlfriend trusts you (which she should, otherwise there's no point in having a relationship), she'll know you have strictly platonic friendships with these women.

My partner has predominately female friends and I am ok with that. He has never given me reason to doubt him and treats me like a princess.
Pick the right partner and she should not dictate who your friends are. More power to you

Hmmm you sound like my boyfriend :b
He is mainly friends with girls, he just gets along better with them I guess! I don't really care that most of his friends are girls because that's how it was when I met him, and I'm not really controlling so I'm not gonna make him stop being friends with them haha. I'm sure of you get a girlfriend that's worth it, she'll understand too! I mean, my boy isn't constantly hanging out with all these other girls, but he does talk to them a lot.
If it's really concerning you then ask your colleagues to go out to the bar or something and you'll probably bond with some of them!

You sound pretty much like my best friend. He will sometimes complain he's tired of being around so many women, and say he wishes he had a buddy, a guy friend to talk to, someone to be one of the dudes with, as opposed to 'the dude'. So what I do once and again is fix him up on buddy-dates with my other friends. He still hasn't found a match, but fingers are crossed. And he has had some fun at least. Try buddy-dating!!

This reminded of me of the movie "I Love you, Man"

i think you might be gay

Those are all great suggestions. I will give them a try. It is nice to know I am not the only one in this situation.

Males aren't like females in social means. Females, in my opinion, are easier to become friends with. To be friends with a malefriend, you should probably do something that involves competitivness, as in you and male friends against others. Do challanges with them, that makes them feel the drive to prove themselves to be able to do something.

Outside of work, where do you hang out for fun? Part of your problem could be that you are always hanging with women, and i'm assuming going places they like a lot. This in itself is not a problem, but it raises two issues making male friends.
1) Other males might see you constantly surrounded by women and think you are gay and prefer the company of women
2) Other males are not usually going to approach a man surrounded by women to hang out with because they are more interested in the women around you and lets face it, men try and single women out as opposed to approaching a large group or one with a guy.