CA State Tax Return with One Spouse domiciled and resident of another state

[peggysioux5]

I found the following information in a Spidell article:

DOMICILE FOR NONRESIDENT SPOUSE
An interesting problem can develop for couples when one spouse is domiciled in California and
the other spouse is a resident of and domiciled in another state. The nonresident spouse would
presumably have California-source income because one-half of the California-source income of the
resident would be attributed to the nonresident spouse. In this situation, the couple must file a joint
return because the nonresident spouse would have California-source income.

My question is "Why is it that the couple is required to file as MFJ and not be able to file as MFS for both federal and CA?"

My situation is that one spouse is a resident and domiciled in CA and the other spouse is resident and domiciled in HI.  One spouse does not want to file jointly for either federal or state due to liability issues of the other spouse.