Yeah from what I can tell in japan it's really really REALLY culturally common for the idea of "YOU NEED BOTH PARENTS" to be hammered in. It seems especially tough for a single dad. It's not so much he thinks he needs to hurry to remarry, I think. It's more any single time he finds something he can't do alone, he'd remember all the times someone else told him he needs to remarry.
It's not that uncommon in the states either....