Hmmm.... I have male friends. Mostly from the boards, the actually who have become IRL friends I hang out with. They are taken otherwise now, and I also hang out with their significant others. Together or separately, but usually in a group. I look at them without gender, just as friends who have experienced something similar and we developed a bond.
I agree with Sunny. Friends of the opposite sex offer a different perspective, and it isn't sexual. Somedays I wonder if I am half-guy myself, haha, so it's fun to have friends who bring out that side in me.
My best friend from 7th grade until I was 22 was male. We never, ever had anything romantic. Heck, we took naps after school in my twin bed, my dad would come home from work and wouldn't bat an eye. I really think it is doable.
My exBF had many female friends. And was friends with his childhood GF. Hung out with her alone often. And was friendly with his long term ex-gf, baby momma. I met her a few times. It didn't really bother me.
I also look at it this way. We are not dating as kids anymore. We are all adults who built lives over the years. Many people, ex's and friends of the opposite are accumulated throughout a lifetime.
Did it bother me a little when I found out exbf had dinner with HS GF? (especially bc she's still in love with him). Yes. I got the jealously twang, because I am human. Do I have the right to tell him he can't hang out with his friend of 30 years? God no! And I wouldn't even want him to if he offered, actually. I don't want to break up friendships. I just trusted there was nothing there on his end.
That was kind of a post in response to you, Maybell, and to the general discussion of being friends with a person of the opposite sex.