It is not allowable for a woman to keep (voluntary) fast when her husband is present without his permission, and she may not allow anyone to enter his house without his permission.
قَالَ رَسُولُ اللَّهِ ﷺ لاَ تَصُومُ الْمَرْأَةُ وَبَعْلُهَا شَاهِدٌ إِلاَّ بِإِذْنِهِ غَيْرَ رَمَضَانَ وَلاَ تَأْذَنُ فِي بَيْتِهِ وَهُوَ شَاهِدٌ إِلاَّ بِإِذْنِهِ
These are some of the a hadith of Muhammad. the Messenger of Allah ﷺ, transmitted to us on the authority of Abu Huraira. So he narrated one hadith out of them (as this): The Messenger of Allah ﷺ said: No woman should observe fast when her spouse is present (in the house) but with his permission. And she should not admit any (mahram) in his house, while he (her husband) is present, but with his permission. And whatever she spends from his earnings without his sanction, for him is half the reward.
عَنْ مُحَمَّدٍ رَسُولِ اللَّهِ ﷺ فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ رَسُولُ اللَّهِ ﷺ لاَ تَصُمِ الْمَرْأَةُ وَبَعْلُهَا شَاهِدٌ إِلاَّ بِإِذْنِهِ وَلاَ تَأْذَنْ فِي بَيْتِهِ وَهُوَ شَاهِدٌ إِلاَّ بِإِذْنِهِ وَمَا أَنْفَقَتْ مِنْ كَسْبِهِ مِنْ غَيْرِ أَمْرِهِ فَإِنَّ نِصْفَ أَجْرِهِ لَهُ
The Prophet ﷺ said, "A woman should not fast (optional fasts) except with her husband's permission if he is at home (staying with her). (Using translation from Bukhārī 5192)
وَقَالَ رَسُولُ اللهِ ﷺ لَا تَصُومُ الْمَرْأَةُ وَبَعْلُهَا شَاهِدٌ إِلَّا بِإِذْنِهِ وَلَا تَأْذَنُ فِي بَيْتِهِ وَهُوَ شَاهِدٌ إِلَّا بِإِذْنِهِ وَمَا أَنْفَقَتْ مِنْ كَسْبِهِ عَنْ غَيْرِ أَمْرِهِ فَإِنَّ نِصْفَ أَجْرِهِ لَهُ
[Machine] And the Messenger of Allah ﷺ said, "A woman should not fast when her husband is present, except with his permission."
وَقَالَ رَسُولُ اللَّهِ ﷺ «لَا تَصُومُ الْمَرْأَةُ وَبَعْلُهَا شَاهِدٌ إِلَّا بِإِذْنِهِ»
"لَا تَصُم المَرْأةُ وَبَعْلُها شَاهِدٌ إلا بِإِذْنِهِ غَيرَ رَمَضَانَ، ولَا تَأذَنْ فِي بَيتِهِ وهُو شَاهِدٌ إلا بِإِذْنِهِ، وَمَا أَنْفَقَتْ مِنْ كَسْبِهِ مِنْ غَيرِ أمْرِهِ فَإنَّ نِصْفَ أَجْرِهِ لَهُ".