All perfect praise be to Allah the Lord of the Worlds. May Allah`s peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
There is nothing wrong with a woman cutting her hair especially if husband asked her to do so for the purpose of adorning to him. In principle, things are lawful, and there is no evidence indicating that this matter is prohibited. Rather, Abu Salamab. 'Abd al-Rahman reported:
"I along with the foster brother of 'A'isha went to her and he asked about the bath of the Apostle (PBUH) because of sexual intercourse. She called for a vessel equal to a Sa' and she took a bath. and there was a curtain between us and her. She poured water on her head thrice and he (Abu Salama) said: The wives of the Apostle (PBUH) collected hair on their heads and these lopped up to ears (and didn`t go beyond that)." {Related by Muslim}.
Commenting on this Hadith, An-Nawawi said: "It proves that it is permissible for women to cut their hair." {Shareh Muslim, vol.5/pp.4}.
The limit to which a woman is allowed to cut her hair for the purpose of adornment varies from one person to another. This is provided that she doesn`t cut her hair with the intention of resembling men`s hairstyle. According to scholars, what is prohibited is shaving her hair. Moreover, some considered this reprehensible while others considered it forbidden. This is attested to by Al-Shirbini who said: "According to the more correct opinion stated in "Al-Majmou`", it is disliked for a woman to shave her head. It was also said that this is forbidden because it is mutilation and imitation of men`s hairstyle, and Al-Awzai` opted for this opinion." {Moghni al-Mohtaj, vol./pp.229}.
Being allowed to cut her hair indicates that she is allowed to go to women`s hair salon for this purpose. And Allah The Almighty Knows Best.