I should hope so. If not the vast of majority of my friends would have to go away.
Being friends with a member of the oppositie sex shouldn't have any more stigma than being gay and friends with other guys, etc. My group of male friends, to be honest, I would never want to date. They are either like brothers to me, or, well, like great friends who you can be stupid around, feel completely at ease even. With them I have "Philia" brotherly love, not romantic love.
Of course, being a heterosexual female, there was some point awhile ago, where there was always the thought of, well, it would be nice to hook up with one of these guys. However once you develop a friendship relationship, that really fades away, because you understand that you could never recover your friendship if you allowed something like that to happen.

That being said, if you are coming HERE to find women to become friends with, I think that suggests a problem if you are married. It sounds like you are looking for something in a person, not the person for herself. You are looking for somebody to fill a role that you haven't been able to satisfy with your current spouse.
It is an entirely different thing to BE friends with a person of the opposite sex as it is to SEEK friends of the opposite sex. Again, most of my friends are guys, but it just kinda happened that way. I just get along better with men. I met my friends at undergrad, or some club, or function, enjoyed the people for who they are, and discounted their gender.
If you are actively LOOKING for a woman, then yes, I think that does not bode well.