No male friends of mine has seen my wifes naked boobs in person -> except one, if that counts...
Just before I came together with my current wife, my best male friend and I went with her on holiday.
We were young and played drinking games and had fun also with some strip dancing - but only to underwears.
One night, we went all to bed and my (future) wife came in our room, only wearing a panty and a top. I can't remember if she had said something before but she just lifted up her top with an embarassed face. We both saw her boobs fully naked for some seconds for the first time for us both.
At this moment that was more funny than hot but today, I wish she would do that again