Walaykum Assalam,
Your husband must pay kafara, however scholars went 2 ways in this situation, whether a woman breaking her fast willingly having intercourse should pay kafara too or no.
The majority of them went with the view that she should pay kafarah, their evidences were:
She has violated Ramadan fast by having intercourse during the day, she must also offer expiation like the man.*
it is a punishment that has to do with intercourse, so it applies equally to the man and the woman, as in the case of adultery.
A woman who went along willingly and was not unaware of the ruling and did not forget that she was fasting is like a man with regard to it being obligatory to make up that fast and offer expiation, because she violated the sanctity of the Ramadaan fast by having intercourse willingly, so she is like the man.
Al-Bahooti Sharh Muntaha al-Iraadaat (1/486)
On the other hand, Imam Shafei and Ahmad went with that she does not have to pay kafarah, but only make up for the day and repent to Allah for such a sin.
Evidenced by this hadith:
Whilst we were sitting with the Prophet (peace be upon him), a man came to him and said: ‘O Messenger of Allaah, I am doomed!’ He said, ‘What happened to you?’ He said: ‘I had intercourse with my wife whilst I was fasting.’ then the prophet told him to pay for kafarah.
Bukhari 1936
The evidence is that the prophet did not mention anything about his wife.
Majmoo’ Fataawa Ibn Baaz (15/307)
A response to this was that the prophet was not asked about the woman, the man came to ask about himseldlf.
So the conclusion: It is safer and stronger to pay kafarah for your sin and repent to Allah.
(Kafara is fasting 2 consecutive months, if and only if you can't then feed 60 poor people).
Allah knows best.