What is this obsession that we have about sex?

Are we obsessed with it because the way we are living we hope to use imagination to deliver us to the ultimate satisfaction we want. With sex we spend most of the day thinking about it, imaging it, in the actual act many are imaging another partner… and thereby trying to bring about a world where my imagination drives me directly to pleasure I want. Thats part of the draw of being an observer right, that we could do that? And we are questioning it.

Isn’t a hell of a lot of our obsession about sex linked to the fact that it is often seen as something to feel shameful or guilty about? For a middle-aged married man who is not turned on by his wife, what is a healthy sex life?