Status Of Marriage
A change in belief after marriage does not dissolve the marital relationship; the couple remains husband and wife. The prohibition against marrying polytheists (which we also extend to atheists) is a separate directive. However, if one spouse changes their faith after marriage, it does not invalidate the union. During the Prophet’s time, after the conclusive communication of the truth (Itmam e Hujjah) to the disbelievers and the subsequent boycott, Muslims were instructed to sever all ties with them, including leaving their disbelieving spouses. However, this directive does not apply to contemporary non-Muslims, as Itmam e Hujjah has not been completed for them, and the associated boycott does not apply. In the case cited in the post, she does not seem to be an atheist if she believes in some concept of a living and active God.