You might not think of it, but naturally the millions of years of evolution that eventually lead to humanity has made it obsessed by reproduction and survival. What makes a human feel fulfilled is always linked to survival in one way or another; it be a good meal, a nice car or an attractive person of the opposite gender; the goal is to stay alive as well as passing genes on. Whether the latter is achieved or not is irrelevant; it's just what the drive and the instincts tend to end up with no matter what the personal motivation is.
I doubt having offspring is too much in the mind of animals in the mating season; it's not really like falling in love with another person makes your head go "kids kids kids", either.
Bookmarks