Why does it seem straight men are obsessed about having anal sex with their girlfriends/wives?

Informative topic breakdown of Anal Sex:

Anal sex for someone who's basically a beginner?
So my boyfriend and I are ready to begin exploring anal sex, but I have a lot of questions. Let me provide a little information first. We're both 31..

What do you think about anal sex?
The title says all!

Are you scared to try anal sex?
I'm a bit hesitant to try anal sex. I just can't see it being any fun. Are you the same way?

Finally had anal sex successfully!
Since I joined Eden I have asked questions and discussed it fairly often here on the forums. Finally tonight though, we were able to have anal sex...

Working up to anal sex
I have had anal sex a few times in the past and it has been extremely painful and unpleasant for me. I'm looking for a product (or kit) that would be.