"Popular Mechanics"

I'll go with question four for this one. The reader never learns in the story why the couple is splitting up, but I assume that he cheated on her. When she says "You can't even look me in the face, can you?" it seems like he should be feeling guilt. It really doesn't matter why he's leaving, though, because the focus of the story is on the way the couple treats the baby. The reason for the split has no impact on the treatment of their child. They act like little kids fighting over a toy. It's like they're too concerned with being angry with each other to notice that they're fighting over a human being that they could easily injure if they're not careful. Based on their reactions, it wouldn't matter if the problem or reason was different. They'd still be fighting over the baby because they're irresponsible parents.