If there was a misunderstanding between the husband and wife and if the husband hits the wife in anger, can the wife hit back?
According to Islam, you cannot do more than the disadvantage which the second person caused …. (apparently)
But I assume it is better to mention that according to the holy Quran,
: «ادْفَعْ بِالَّتی هِیَ أَحْسَنُ»
Fend (repel) the hardness(badness) by goodness
Of course seemingly according to Islam, (in the mentioned issue if someone hits you), you should get Diah(atonement or الدیه) of his hitting instead of hitting him back.
But you'd better do not hit him back, since it would increase the argument ...
Looking at the narration below could be profitable for you. It has narrated from Imam Sajjad (a.s.) as the fourth Imam of Shia Islam that he said:
Not only goodness by goodness, haply answer the badness by goodness.
Accordingly, isn’t it better to forgive people and answer their badness by the goodness?
At the first place, there is no hitting each other in anger in Islam. Everyone is supposed to be patient and forgive each others' deeds. Hitting is not the solution.
Although, this is a bit out of context, but I thought could be helpful,
And if you fear dissension between the two, send an arbitrator from his people and an arbitrator from her people. If they both desire reconciliation, Allah will cause it between them. Indeed, Allah is ever Knowing and Acquainted [with all things].(Qur'an 4:35)
Moreover, a woman, hitting back would worsen the situation simply. And I don't remember a single situation, during Prophet's(pbuh) time where a lady hit her husband. So, it would be better if you don't hit back and forgive and remind each other to be patient.
...But what is with Allah is better and more lasting for those who have believed and upon their Lord rely. And those who avoid the major sins and immoralities, and when they are angry, they forgive, And those who have responded to their lord and established prayer and whose affair is [determined by] consultation among themselves, and from what We have provided them, they spend. And those who, when tyranny strikes them, they defend themselves, And the retribution for an evil act is an evil one like it, but whoever pardons and makes reconciliation - his reward is [due] from Allah. Indeed, He does not like wrongdoers.
(Qur'an Surah Ash Shura 42:36-40)
The prophet(pbuh) said,
"The best deed before Allah is to pardon a person who has wronged you, to show affection for relatives who have broken ties with you, and to act generously towards a person who has deprived you". Thereafter he recited the following holy verses: "Turn to forgiveness and enjoin good and turn aside from ignorant" (7:199). Qatadah was asked, “Which person has the highest standing?” He replied, “The one most abundant in his pardon.”
May the creator guide us all.
Support: Forgiveness and also from the answer of اللهم صل علی محمد و آل محمد