Anyone that has character leaves a mark on another. Would you like to leave the world without making a ripple?
Action, reaction, motivation, emotion, all have to come from the characters. Writing a love scene requires the same elements from the writer as any other.
I think writer is a word without gender, and a good writer observes, absorbs, hopefully empathizes then translates that into character and story. You don’t have to do or be or have experienced, traveled to, but you have to imagine all of that, very well–and believe it completely during the bubble of the work.
The most important aspect of any story, to me, is character.
Actually, I find it great fun to develop family series with lots of characters.
I don't base any character on a real person, and really don't do composites either. I make them up.