Strange Point Of View?!

So my fiancé made the strangest remark last night when we were out and about with a few friends.... Somehow they were talking about "(when living in a small town) you don't lose your girlfriend, you just lose your turn"... They all tought it was really funny and true... I've always moved around a lot and lived in various places around the world, so I wouldn't know. I've never been in a situation like that... So I said that. Then my fiancé asked "so you've never been in a situation where your friend is dating your ex, or you are dating your friend's ex?!" When I told him "no", he said "then you've never lived!"
I was a little in shock and that conversation somehow still bothers me. Any comments?!