Fiduciary Duties Between Spouses

Spouses should be fully aware of the fiduciary duty owed to one another as well as the remedies available for the breach of the fiduciary duty.
Spouses are economic partners from the date of marriage until the date of separation, and the economic partnership imposes fiduciary duties such that neither spouse may take unfair advantage of the other with regard to property transactions. Further, the fiduciary duties continue with respect to community property – even though the parties have separated – until the community property has been divided by the parties or by the Court (Family Code section 721, Law Rev. Comm. Comments, Commentary).
Either spouse may enter into a property transaction with the other, or with any third party, as he or she could if unmarried. (Family Code section 721(a).) 
However, in transactions between themselves, each spouse is “subject to the general rules governing fiduciary relationships which control the actions of persons occupying confidential relations with each other.  This confidential relationship imposes a duty of the highest good faith and fair dealing on each spouse, and neither shall take any unfair advantage of the other.  This confidential relationship is a fiduciary relationship subject to the same rights and duties of nonmarital business partners, as provided in . . . the [California] Corporations Code, including, but not limited to, the following:  (1) providing each spouse access at all times to any books kept regarding a transaction for the purpose of inspection and copying.  (2) Rendering upon request, true and full information of all things affecting any transaction which concerns the community property.  Nothing in this section is intended to impose a duty for either spouse to keep detailed books and records of community property transactions.  (3) Account to the spouse, and holding as trustee, any benefit or profit derived from any transaction by one spouse without the consent of the other spouse which concerns the community property.”  (Family Code sec. 721(b) [emphasis].)
Apart from those found in Family Code section 721, remedies for the breach of a fiduciary duty can be found in Family Code sections 1100 and 1101, including payment of an amount equal to 100 percent of any asset undisclosed or transferred in breach of the fiduciary duty where there is proof by clear and convincing evidence of malice, oppression, or fraud. (Family Code sec. 1101(h), Civil Code sec. 3294.)