Some things don't change: Pesachim 91b

There's a pattern that is so common that it is the stuff of jokes. The gentile half of an interfaith couple converts to Judaism, and becomes much more strict than the Jewish-from-birth half, sometimes to the point of tension in the relationship. Converts in the time of the Babylonian Talmud showed great, perhaps excessive piety, as is shown by the below passage:

Rabbi Ya'akov says in the name of Rabbi Yochanan: One may not make a group [that shares a Passover sacrifice offering] which is wholly composed of converts, lest they be very particular and improperly determine the sacrifice is flawed.