Maybe the sleepy marriage proposal was like a ... climax of short? or the author got busy with something else, I want to believe the second, can't accept if it was an axe, author would get noticed weeks or months before.
Regular romance ends with getting together, so manga where they're already together ends with marriage? Makes sense in a way, although considering the kind of story this has been, it really wouldn't change that much. And there are still so many plot lines open...
And yes, it would certainly be nice to see a new major work from the author. The bite-size episodes here have been nice, but I'd definitely welcome a new story with full length chapters.