By California law each spouse owns half of all community income, and community income must be divided equally when filing separate returns. That being the case, it appears that your husband's share of the community income would be taxable by his resident state of Virginia - since Virginia taxes its residents on any income that is taxable on their federal return. Your husband's share of the community income is taxable on his separate federal return.
From the Virginia Administrative Code:
"For the purpose of determining Virginia taxable income, the term "federal taxable income" means all income from whatever source derived and however named on which a federal income tax is imposed."
https://www.law.cornell.edu/regulations/virginia/23VAC10-120-100
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
