Nedarim 89 - A vow of a widow
The Torah said, " A vow of a widow shall stand ." But this is obvious, for who could potentially annul a vow of an independent woman? So why are these words necessary? - This teaches the following case: if she took a vow while being a widow - for example, if she said that she will have something prohibited to her after thirty days - and then she got married. Such a vow the new husband will not be able to annul.
Conversely, if she vowed while being married, and her vow was to take effect after thirty days, and the husband annulled it, but later divorced her. Even though by the time thirty days pass she is not married any longer, his annulment is valid, and her vow is not effective.
If she vowed, then divorced, and then her husband re-married her, he can no longer annul her vows. This is the general rule therefore: if she has been on her own even for one minute, the husband can not longer annul her vows.
Art: A Proposal of Marriage By Jules Worms