Legal Question in Family Law in California

Not unless the change in the taxation on her income due to it becoming part of your joint income increases her take-home pay. It is possible that your joint income will push her into a higher tax bracket and reduce her take-home pay (the so called "marriage penalty"), in which case her support could be increased. Bottom line, though, the change would be modest, and would only happen if one of them filed a motion to modify support.