I'm sure other people have done this. I'm just looking for insight into the psychology(sex related.)

Okay so here's the scenario:

A chick, let's call her Cindi, I'm in a FWB relationship has recently starting seeing a new guy. Let's call him Todd. Todd's been asking Cindi a lot questions about her previous partners. He's been especially interested in the "biggest" guy she's ever been with. I just happen to be that guy.

He would ask her questions like "What did feel like?" and "How does it compare to other guys?" Real in depth questions. Eventually it go to the point, Todd asked Cindi to see a picture of my penis. She obliged him and it upset him and made him uncomfortable.

To note: My penis is above average, but not freakishly huge or anything crazy. Apparently, Todd is a bit below average.

I've never once wanted to know anything about exes or past lovers. I'm not sexually threatened in anyway by a girl with history, but I think if I saw a picture of a dick much bigger than mine it would give me a complex.

What drives a person to get this obsessively inquisitive? Have any of you done this, and regretted it? Are women interested in comparing themselves to naked pictures of exes?

TL;DR Guy wanted to look at pictures of my bigger dick. A dick which banged his chick. Why?