It was not connected to any family member or close relative.
It just so turned out that in my early years I didn't have the guts or wasn't cocky enough to hit on girls, I was good to them and respectful.
So because of this first, when I was around 10 or 11, fell for a neighborhood girl my age. We were close friends and both knew we liked it other, but I didn't make the move. You know who made it - one of my close friends, which was ok, he didn't knew what was happening, he offered her to be his girl and she accepted, even when she knew I liked her, I just didn't acted.
After that I fell for a classmate, was walking her to their place,hanged out with her, but same story. Didn't act on it so another classmate took the initiative.
Now in both cases thing were happening before my eyes. I was watching how the girl I had feelings foe accepted another boy to touch her body, but breasts, kiss her. In the later case the girl from my class on several occasions blew my buddy in my presence, which made me fucking aroused. I actually enjoyed watching her do it.
So I think this is what led to liking such things.