Is his 'childhood friend' flirting with my husband?

[Substantial Monkey]

Isn't that the definition of being in the friend zone, when the words friend and love are used almost in the same sentence? I don't think you have anything to worry about. But I do find it curious how you married him and seem to know barely anything about the nature of their relationship. If I was friends with someone for 15 years, I'd at least bring them up in conversation with my wife/fiance from time to time if in-person introductions weren't possible. I'd definitely explain what exactly our relationship is. I'm sure they are very close, like brother and sister. But if it's anything like the relationship I have with my opposite gender best friend of nearly 15 years, an intimate or sexual relationship is simply not an option or even considered. I suppose at times a sort of flirty verbal exchange happens but it'd be like trying to get it on with my sister or family. If either of us wanted something to happen, it would've happened a long time ago. And telling him or somehow getting him to never see or talk to her again will do nothing to curb your feelings of jealousy because nothing actually got resolved or sorted out. It would only serve to reinforce and strengthen the jealousy when the inevitable day comes when a friend of 15 years needs something in the future. Or even worse, the relationship simply becomes secret and hidden from you and that would only make your feelings and doubts worse.

I think you should talk to him again. Don't be confrontational or sarcastic or angry or focus the conversation about your jealousy or perhaps resentment. It may prompt a more defensive response from your husband since the subject has come up a few times already. After all, he can't control what she posts on facebook. Accusing him or being confrontational with him about what SHE posted will only prompt defensive and nonproductive communication from him. Simply be matter of fact and calm and objective. Figure out what exactly you don't know about their relationship that causes you to feel a little jealous. I think you should ask him why he never had an intimate relationship with her. When you understand why, then maybe you'll have a better idea of what it is that only you offer him that she doesn't and you won't be confused as to why he married you instead of her. Jealousy is a normal response, but nothing good ever comes from it when acted upon hastily. Consider this your first test in maintaining open communication in your new marriage.

[Love]

write on her facebook "I hope one day you find a love like what _____ and I have"