Or can I just use my own income?
Do I have to list my new spouse's income on FL-150?
If the issue is related to child support and you are filing taxes jointly with your new spouse, or the issue is spousal support for your ex-spouse, yes, you’ll need to list it. For the former, while your new spouse’s income is not used for calculating child support, the income does affect your tax bracket. For further information, review the following article from our website, specifically step 2, under the sub-heading “new spouse income.”
https://cristinlowelaw.com/california-child-support-in-ten-steps/
As for the issue of spousal support for your ex-spouse, it is relevant for purposes of determining your income available for paying spousal support and assessing your current standard of living.