Like her husband, Marilyn does not approve of Sue's marriage to Frank (though she's more lenient towards Frank unlike Stan). When they come to visit them at the lake, it is revealed she and her husband had been secretly sending Sue money to help out the family.
Marilyn came to Sue's baby shower where she was disappointed to see that Sue was not excited over her pregnancy.
She also fawns over Sue's college friend, Gert Gerski, a lawyer, and tells Sue she never expected her to be successful, while Sue thought the exact opposite.
Marilyn and Stan have a son named Louis, whom they disowned after learning he is gay.