Mishnayos Nedarim Perek 7 Mishnah 9

If he said to her: Benefit from me until Passover if you go to your father’s house from now until the festival of Sukkot is forbidden for you, and she went to his house before Passover, it is prohibited for her to derive benefit from him until Passover. If she derived benefit from him before Passover and went to visit her father after Passover, she is liable for violating the prohibition of: He shall not profane his word (Numbers 30:3), as the condition was fulfilled and she violated the vow retroactively. If the husband vowed: Benefit from me is konam for you until the Festival if you go to your father’s house from now until Passover, then if she went to his house before Passover, it is prohibited for her to derive benefit from him until the Festival, and it is permitted for her to go to her father’s house after Passover, as that time period is not included in his stipulation.

שֶׁאַתְּ נֶהֱנֵית לִי עַד הַפֶּסַח אִם תֵּלְכִי לְבֵית אָבִיךְ עַד הֶחָג, הָלְכָה לִפְנֵי הַפֶּסַח, אֲסוּרָה בַהֲנָאָתוֹ עַד הַפֶּסַח. אַחַר הַפֶּסַח, בְּלֹא יַחֵל דְּבָרוֹ. שֶׁאַתְּ נֶהֱנֵית לִי עַד הֶחָג אִם תֵּלְכִי לְבֵית אָבִיךְ עַד הַפֶּסַח, וְהָלְכָה לִפְנֵי הַפֶּסַח, אֲסוּרָה בַהֲנָאָתוֹ עַד הֶחָג, וּמֻתֶּרֶת לֵילֵךְ אַחַר הַפָּסַח: