I have a male friend, I've known for a long time, we get on well, but I have never seen him as anything but a friend. We have some interests in common, that I don't share with Dh, so we spend some time together on those, with our partners' full knowledge and agreement.
Recently, we've been having a lot of putting the world to rights conversations and talking about our earliest memories/ teenage love lives etc. Things that you would talk about with a close girlfriend, but not an acquaintance iyswim.
I can't really put a finger on it, but I'm not sure if some mark has been overstepped. I don't find him attractive and am completely happy and confident in my relationship with DH, but wonder if I need to pull back a bit. It would be a shame, as we do have fun together, but I wonder if that's part of the problem?