Legal Question in Family Law in California

A new spouse's income is not even considered in the determination of child support (much less spousal support), other than to determine taxes.

I don't think Ms. Ellifritz is addressing your particular question, though she is right about what she says. Whatever support he is ordered to pay is ordered, and you are not asking about recalculating support as I understand it. You are asking how to collect the back and current support. The answer is that you cannot collect from her income directly, such as by garnishing her wages. Her income is, however, community property and you can collect from his half once it hits a joint account. Your simpler and more direct path, however, would be to haul him in front of a judge on an Order to Show Cause re: Contempt of Court. At that hearing the judge can order him to find work, and give him jail time if he refuses.