I have a facebook friend who is a person I know from my city, but not well - I would call him an acquaintance. We met at a community arts group, and have interacted on facebook mostly having topic based discussions about topics we are mutually interested in - until now. Recently he has started commenting on my posts with humorous comments that have trended more and more towards innuendo and flirtation. He is a pretty witty person so these aren't really overt comments, more based around subtext, but I had a friend read them over and she confirmed that they are definitely flirty - stuff like joking about us running off together to start an orchid farm and stuff that would be funny if it was one of my female friends or some of my male friends who I have that type of relationship with, but he is more just some random dude. I am wondering what a polite way to say "hey buddy, I'm engaged, knock it off" is? He's been introduced to LordL, and I have mentioned him as my fiancée in conversation at least once and I'm listed as engaged on my profile, so he shouldn't be misunderstanding my relationship status for any reason. I don't want to make it awkward when we see each other at the arts group though. Another friend suggested saying "hey, your comment about the orchid farm was funny but my relatives might wonder why you're talking about us running off together considering that I'm engaged, do you mind toning it down a bit?" or something to that extent.
Is there a polite way to enforce a boundary here without making our arts group meetings unbearably awkward? This guy may be one of those people who flirts with everyone harmlessly or an evil homewrecker wannabee - I have no idea, that's part of the problem.