Before my fiancee, I've never had a serious girlfriend - as in someone that I'd been dating for 3+ months and formally introduced to my parents and close friends. However, I've had plenty of dates and girls who'd been around for a short time up to around the 3 months mark. I never lived with them though. Nobody ever seemed to think that it was weird, while I was still single. My male friends envied my lifestyle, especially my freedom. The girls I know were intrigued, and later got very jealous when they met my fiancee. Older relatives and family friends would keep telling me to stop playing around and get married. I think it's because to them I come off as a man who can get a girlfriend easily enough but chooses not to.
I have a few male friends though who come off as fairly clueless about women and have never had a girlfriend because they can't get one, and people do treat them like they're weird.