I think a related issue is that EVERYONE is doing bb now because PREP is out there, at least in the US. And HIV isn't the killer it was, thankfully. Seems to be more bb fucking than past 30 years, and everyone it talking about it and DOING it. Trust me - I've been here the whole time, and now travel a lot and hear what guys are talking and doing. So now, taking loads on PREP is just like the bottom next door at the bathhouse - he's doing the same things.
Yeah, its great that we have it, and its fucking awesome taking dick and loads. But some of us live on the edge, all about being different, or something like that. Our festish is doing what most guys won't do. When you take PREP you are preventing the very thing that is so desirable in your head. So if you have eroticized bb fucking to the point of thinking poz as a fetish, doing it on PREP is safe, and that's not what your brain wants.
Find a good friend that you can talk to about all of it a good deal, and think long and hard about it. Reality bites.