Under California law, the first spouse has the initial burden of proof to establish that her marriage has not been dissolved. The burden of persuasion then shifts to the second wife to establish that the first marriage had been dissolved. Otherwise, the first wife is deemed to have established her status as the lawful wife.

The legality of a marriage between persons sui juris is to be determined by the law of the place it is celebrated. Although our statute declares a marriage between an uncle and niece to be void, our statute does not state that we cannot recognize such a relationship that is valid in another state. [...]

A court cannot declare a prior marriage dissolved and a subsequent one valid if such a declaration would have the effect of disinheriting the spouse of the earlier marriage without any offsetting advantage in terms of the legitimacy of children or the sharing in the estate by the spouse or children of the second marriage. The cases that have held the subsequent marriage to be valid are based on public policy for upholding legitimacy or favoring the participation in the decedent’s estate and preserving the validity of a marriage when there is no strong public policy that would be served by doing otherwise. [...]