Narrated Ibn 'Abbas:
Once Allah's Messenger (ﷺ) came out while Bilal was accompanying him.
He went towards the women thinking that they had not heard him (i.e.
his sermon). So he preached them and ordered them to pay alms.
(Hearing that) the women started giving alms; some donated their
ear-rings, some gave their rings and Bilal was collecting them in the
corner of his garment.
Bukhari 98 and Muslim 884
we can see from the hadith above we don't meet an explanation that the women need to ask their husband's permission first to give alms when Prophet Muhammad PBUH ordered them to give alms.
the freed slave of Ibn `Abbas, that Maimuna bint Al-Harith told him
that she manumitted a slave-girl without taking the permission of the
Prophet. On the day when it was her turn to be with the Prophet, she
said, "Do you know, O Allah's Messenger (ﷺ), that I have manumitted my
slave-girl?" He said, "Have you really?" She replied in the
affirmative. He said, "You would have got more reward if you had given
her (i.e. the slave-girl) to one of your maternal uncles."
Bukhari 2592 and Muslim 999
In this hadith, the Prophet PBUH did not blame the actions of his wife, Maimunah, who spent her personal property without his knowledge and permission. If this was forbidden, the Prophet PBUH would have reprimanded her.
Asma' reported Allah's Messenger (way peace be upon him) as saying (to
Spend and do not calculate, (for) Allah would calculate in your case;
and do not hoard, otherwise Allah would be withholding from you.
Bukhari 1434 and Muslim 1029
In this hadith the Prophet PBUH ordered Asma to spend a lot and the Prophet did not order her to first ask permission from her husband, namely az Zubair. If it was a necessity, the Prophet would have ordered it.
It was narrated from 'Amr bin Shu'aib, from his father, from his
grandfather, that the Messenger of Allah said: "It is not permissible
for a woman to give a gift from her wealth, once her husband has
marital authority over her." This is the wording of (one of the
An-Nasa'i 3756, Hasan according to Darussalam. Ibn Majah 2338, Sahih according to Darussalam. Abu Dawud 3546, Hasan Sahih according to Al-Albani.
We compromise this hadith with the hadiths above by saying that one of the forms of good association between husband and wife is that if a wife wants to spend her personal property to buy something or donate, it's recommended for her to tell her husband first. This is the adab that a wife should have and it is better.
Translated from this article.
and Allah knows best.