Thanks for sharing your story!
Some guys would get obsessed in the wrong way about this. But it sounds like you are enjoying it and using it to ramp up your sex life. Power to you bro!
I had a similar experience with my girlfriend (not a wife, so I know its doesn't have as much gravity, but we have been together a long time) When we first started dating I knew she had been with this guy before me from the restaurant she used to work at. He was kind of a prick, cocky and aggressive as fuck, but was in our friend group so we knew each other and had to be around each other some times.
It wasn't a big deal, I know I make her cum many times in a session and she has to warm up to take my full cock, so I was not worries about my size / our sex life. But eventually it came out when we were drunk that he was the biggest she had ever had. That it was 9" and very thick. She had a few photos of him on her phone and eventually she showed me after I asked to see them while we were drunk. She warned me but I insisted. He was massive! He had a huge uncut cuban cock. There is one photo of his cock head resting up against what is clearly her pussy, that is burned into my brain even now years later. For a while I got obsessed with it/him, and would get agitated when I knew he might be at a party or something we would go to. He was kind of an ass anyway, but knowing he was bigger than me really messed with me. I am 7" and rather thick, and have never had any complains about my size, but I was younger at the time so I was a bit immature about it. Not proud of this, just being honest here on a site where other guys might understand this sort of thing.
Eventually I changed my outlook and started using it to ramp up our sex life and try harder to give her the best sex I could. It made me a better lover at that age in your mid 20's when you (I) went from just having horny young man sex, and probably being a bit selfish, to fucking for hour on end and really making sure to give her pleasure and fuck her strong. I also realized they guy was kind of unhappy, perpetually single, and generally just known for hanging a huge dong who would fuck anyone and a string of women who ended up all hating him. Where I was with a beautiful women who I fuck many times a week, and have a satisfying sex and romantic life with. I think I got the better end of it.
@hugetex Hope you make the right choice about seeing the videos if it comes to it. Just remember you can't unsee it.
Good luck man!