Conversation I had with a buddy recently:
As we've gotten older, the things that used to turn us on aren't the same things at this point in our lives. He said something like: "Ever since my wife gave birth to our first kid, I just view boobs differently. It's not that they are a turn off, I just don't see them as something that can instantly take me from 0 to 100 anymore. I guess I'm just desensitized by them."