Why would anyone tell someone else they have high blood pressure? You're right, it's not that big a deal. If it's well controlled, you don't have to say anything, right? Are you going to say "I have blue eyes?" Come on, now, don't be ridiculous.

I might be nuts but I think the time to tell is when it naturally comes up. You get flustered, and he seems confused - explain it then. Otherwise, just like everyone else, there's no need to talk about your medical quirks.

If you make it a big giant reveal, he might think you're going to do a Jekyll and Hyde trick on him. You're not, right? So why make him worry about something completely unnecessarily?