I’d imagine those who married a Sephardic wife have the same problem with their in-laws eating kitniyos.
Ive been told by people in Israel that Kitnoyot is sort of falling by the wayside there because there is alot of intermarriage between Sephardim and Ashkenazim in all communities except the charedi ones.
Its not so easy to go to your Mother-In-Law and not eat her food and not let the grandchildren eat Savta’s cooking