I think that's not quite an exact match to our situation - Manhatten IS splitting his attention, he's just basically omniscient; whichever Kakara you're with is an entire, self-contained person, to the point where they prank one another. Multiform is a reasonably well-understood technique, instead of a weird surprise like Dr M, and finally people have weird hangups about romance in general.
Basically, I think it's pretty likely it's not a problem, and I'd at least want to wait for someone to mention it before assuming the worst and limiting ourselves unnecessarily. Especially since if it is a problem, the expected outcome is for someone to bring it up, rather than jumping to being super offended.