Hanna--
I disagree with your comment that Margaret doesn't know for sure if her love is gone during "Dividing Day." She sings:
I can see the winter in your eyes, love, telling me:
'Margaret, we did it. You courtsied, I bowed.
We are together, but no more love, no more love allowed.'
I think these lines indicate she's pretty sure Roy no longer loves her.
My interpretation of their relationship, judging by the line "we did it", is that the Johnson's marriage was based solely on raising Clara, not on love between husband and wife. And now that Margaret is facing the possibility of Clara leaving, the Johnson's relationship is over. There's nothing more to do ("You curtsied, I bowed"). And now Margaret is questioning if their marriage was loveless from the start.
On the road of life, do not pause for suicidal chipmunks who freeze in your headlights, seeking death by your tires...