I guess like everything a little backstory and context helps. I have been with my wife for 3 years now I love my wife, she is with out a doubt "the one". 

She has a group of friends that she grew up with and went to middle and high school with and she still has remained good friends with a lot of them. I think they are a wonderful group of people and generally everytime we get together it's a great time. They are a very welcoming and hospitable group and I had no problem falling in on friendly terms with a lot of them. The majority are over/out for dinner monthly.

I have slowly started to notice that almost everytime we get together a subject (almost always jokingly brought up) is another one of our friends ( let's call him Jeff ) who has a, as some have referred to it " the biggest dick they have ever seen" "not big, like freakishly huge" "you have your regular virginity, then your Jeff virginity" type of endowment. 

That being said it just seems like everyone in this group has some kinda fetish-worship about this guy and his hog, like I mentioned before, the jokes and stories they all share about different times they themselves have had sex with Jeff, or times they walked in on Jeff having sex with someone. I pointed this out to my wife after dinner Saturday about the cult like worship and her response was. " I mean it is freakishly huge *laughs*"

My problem with a lot of this is more complex than the way that everyone seems to obsessively talk about this guys hog. Some of it stems from the fact that my wife had a "FWB" relationship with him for a few years. ( 10 years ago, long before I ever met her) A lot of it I feel comes from the fact that everyone is comfortable OPENLY discussing this man's sex life.
Maybe this is where I start to sound prude or like a baby but I don't openly discuss the kinds of kink my wife and I are into. I feel like everyone just being so nonchalant about discussing the first time they saw Jeff naked or the first time they saw Jeff fucking some random chick at a party is just.... too much

The whole thing just feels weird to me, with all of the different factors adding up, sometimes it just makes me reluctant to even agree to go out to dinner because at the end of the night regardless of where we go or what we do at some point this subject is going to be brought up and yet again I'm going to be forced to either confront the idea that my wife had sex with this guy for years or ignore it.

I have tried to talk to my wife about it but at the end of the day, if the tables got turned I don't see any of it happening much less being so accepted. I would be mortified and embarrassed to sit across the table from an ex girlfriend as everyone else traded stories about having/seeing her having sex.

TL;DR

AITA for slowly over time wanting to exclude myself from group plans with my wife and her circle because of the constant inappropriate joking subject matter about her ex-bf/fwb's massive endowment