Is the wife obligated to fulfill her vow to fast on Mondays and Thursdays for life after her daughter's birth was facilitated, knowing that she did not consult her husband about this vow?

If you permit your wife to fulfill a vow, she must do so, for the Prophet, peace and blessings be upon him, said: "Whoever vows to obey Allah, let him obey Him." If you do not permit her, you may prevent her, and she is not allowed to fulfill it, as your right takes precedence. If you prevent her, she must make it up whenever she is able. As for expiation for breaking an oath, the majority of scholars hold that it is not obligatory, whereas the Hanbalis consider it obligatory. If she is unable to fulfill the vow and make it up, then only an expiation for breaking an oath is required of her.