This is a part in the child support laws in my state, can you break this down for me?

Sounds pretty simple, as far as what they consider your income they don't consider your "community property" such as cars, or a home as part of your income, but it says ordinarily which sounds like they could use it as part of your income but more than likely won't. Like it said unless compelling reasons exist. As far as a spouse, well if he or she isn't the parent it doesn't sound like they will take their income into consideration either since its not their child. You might want to talk to a lawyer about this, but that's what it sound like to me just from reading it. I guess compelling reasons exist would mean there's evidence that you rely on that other person for their income as well.