Hey Phoenix.
I'm impressed by your well thought consideration of your sexuality in your posting. I'm convinced that whatever you decide will be the right decision for yourself. What's right for others may not be the same thing that is right for you.
It sounds like your struggle is in balancing your desire to be the sexual person that you are, with wanting to stay HIV negative, and also increase the pool of hot guys to be with, knowing that many of us are HIV poz
I think it is entirely possible to have both: to be highly sexual and to have a harm reduction strategy to stay HIV negative. Given that you wish to top is reducing most of the risk right there. Some guys are very comfortable topping poz guys knowing that there is less risk from being a top. Though again, what is right for others is not necessarily right for you.
I do challenge you to look at your strategy if it is currently to only fuck guys who say that they are negative. As I think you know, and others have pointed out, poz or negative is not so black and white. Yes, there is no HIV risk from a true negative guy, but within the pool of guys who identify as negative are guys who are recently poz and don't know it. Also a guy who recently converts will have an initially very high viral load right after conversion - which gives the greatest chance of transmission, until his viral load either comes down on its own, or he discovers his status and then starts meds. If you wish to continue fucking "negative" guys, you may want to ask a few more questions, such as how often do they get tested, and how often do they take loads from unknown status guys.
The known quantity (poz, undetectable) may be a lower risk than the unknown quantity (possibly neg/possibly poz with a high viral load).
So while It is your choice of what you are comfortable with, you may want to consider that fucking poz, undetectable guys may really be a great harm reduction strategy, and may ironically reduce your risk over fucking only neg guys.