Fantasizing Over Other Men and Sharing

Hey guys. So I'm currently dating and exclusive with someone and while it's great I'd say 70% of the time, the other 30% can be 'not exactly what I'm looking for'.

Long story short, my man loves to keep dudes around forever. Exes, almost exes, etc. I'm not really threatened by this but the other day he got a DM from one guy who he has told me about before. He has told me he really liked this guy and pursued him but nothing happened. The DM was harmless, just a question but then my boyfriend went into a rant about how much he really liked him and how he knows through a friend that he has a really great dick and the whole thing left me feeling like he really wants that guy 💀.

I gently expressed concerns about his priorities and he went into even MORE detail about it wasn't just about his dick, the guy is successful, funny, smart etc. He could tell I was bothered but what does one actually SAY in this moment? I simply told him, "No one wants to hear their guy gush over some old obsession". I don't really want to hear him gush and fantasize over other dudes in my face but, am I being unreasonable?

The obsession with dudes he never had/hasn't had yet/ didn't get to date fully feels real and seems to run deep: alot of old pictures of exes, saved galleries, etc. that he looks at alot.

All of this has me thinking that short-term it's great but any expectations for long-term should really be reigned in.

What do you all think?