Does the principle of res judicata apply in the context of a former husband's claim against his ex-wife?

In a context reasonably similar to that of the case at bench, the Fourth District (Div. One) held in Kelley v. Kelley (1977) 73 Cal.App.3d 672, 141 Cal.Rptr. 33, that the principle of res judicata did apply. The court said (p. 678, 141 Cal.Rptr. p. 36): "Here (the former wife) was fully cognizant of (the former husband's) status as retired and was aware of the fact he was to receive a pension. She was, however, mistaken as to her legal rights to that pension. She elected to decide the merits of a claim without aid of legal counsel and personally contributed to any mistake as to the character of the property. (The former husband) was not a party to that mistake and did not conceal the facts or otherwise participate in any wrongdoing. (P) The judgment is res judicata and there is no basis for equity to interfere."