My DP has a female best friend. They share what could be described as flirty messages quite frequently, but I know her and she is nice, and I trust him, so I've not really minded. By flirty it's not sexual or anything like that, it's just quite jokey. I've heard him say 'I love you' once to her, but he says it's the way you love a friend, and I believed him. He said she's like a brother or sister to him, which is fine.
Today we were chatting, and he admitted than he fancied her before we got together, and considered pursuing a relationship with her, but decided they would not be compatible. It did not go any further. She has no idea, and they've never talked about it, kissed etc.
He says he doesn't fancy her anymore, and they're now just close friends.
Do you think it's possible to un-fancy someone in this way whilst remaining extremely close to them?