Depending upon where they live, it's also possible that he has Seasonal Affective Disorder. I'm a night owl with SAD (oh the irony), and in the winter, my sleep schedule gets incredibly out of whack--it's hard for me to get to sleep before 2 a.m.. Plus the fact that it's just damned hard to get up when it's dark outside. (I have no idea how "morning" people do it when it's not even morning; there's no sun!)

The only thing that works is discipline, and it helps that I'm sensitive to noise in the first place. I'll never win any prizes for timeliness, but neither do I stroll into work an hour and a half late (at least, not any more). Gadgets help; for about 3 months of the year, I have my bedside lamp plugged into a Christmas tree timer, so that my radio and the light go on at roughly the same time.

If the BF cannot or will not address his sleep problems, or if the LW cannot or will not have the patience to work with him on them, might I suggest separate bedrooms? If everything else is great, with the exception of their sleep incompatibility, why throw the baby out with the bathwater?