In my experience, boiling as you described is unnecessarily messy, adds brewing time, and kills some delicate flavors (and probably attracts bees, if it's summer and you have the windows open). Despite the occasional anecdote to the contrary, boiling/pasteurizing your must isn't going to make your honey any more "sanitary" by itself. If something is spoiling a batch of mead, then it's going to be because something was introduced via poor sanitation practices (improperly sanitizing carboys, using water straight from the tap, making unsanitized fruit additions, etc.).
Honey, much like sugar and salt, is naturally hygroscopic (ie, it sucks all of the moisture out of things), which prevents organisms such as bacteria and yeast from living in it. This is the main reason it is said to have an "infinite" shelf-life, as spoilage organisms can't really live in it long enough to get a foothold.
That said, there's nothing saying that you can't pasteurize your must, it's just that you don't need to. It used to be standard practice, but has since fallen out of favor with most meadmakers. In The Compleat Meadmaker, even Ken Schramm admits to not really doing it anymore, even though the basic "starter" recipe in there calls for it (I'm at work right now, or I'd grab you some page numbers).
tl;dr As long as you sanitize properly, you should never need to boil your must. If you do need to take heat to something, that "something" doesn't need to include your honey.