What is the ruling of the Sharia on a fiancée who repeatedly spends her nights outside her family's home, insists on visiting her family daily after marriage, and the suitor bears exhausting financial and marital burdens?

A wife is not permitted to leave her husband's home to visit her family or anyone else without his permission. The preponderant opinion is that the husband should permit his wife to visit her family to the customary extent. Explain to your fiancée that obedience to her husband in what is right is more obligatory than obedience to her parents. If she does not agree to this and the marriage contract has not yet been concluded, there is no blame upon you for leaving her, as an engagement is a promise of marriage that may be annulred for any valid reason.