More than often Marceline had to sing and play the bass not to get rusty (in case the band would go on a tour) and Bonnibel had some reading to do (about so astrophysic stuff that Marceline never got). More than often that left little to no time for them to be with each other.
But in the end they found a compromise didn’t they ?
Art © ~Zell-K
Adventure Time © Pendleton Ward