When I met my wife back in 1985, she was heavy into disco and had never heard a high-end system. In 2001 she bought me my Focals as a birthday gift.
Now she is into a lot of my old classic rock and blues, and I will often play Prince or the soundtrack from Saturday Night Fever during our listening sessions. She won't admit it often, but listening to crappy little systems really annoys her and despite it all, she recently admitted that she has developed into a "golden eared snob". From the Cream 2005 reunion tour through some classical and Sarah Brightman and all points in between, music is now at the heart of our relationship. She just leaves the equipment and technicalities up to me, including designing our living rooms around the system placement. Choice of music should be mutual. And then there is our common passion for the Moody Blues, which is a subject for another thread.