All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
A wife is not Islamically obligated to serve her mother-in-law, as we have already highlighted in fatwa 84909. Also, the wife is not obliged to live with her husband's family (her in-laws); rather, she has the right to live in a separate house where she feels secure and does not face any embarrassment by the presence of his family. It might be more appropriate when he travels to leave her with her own family. For more benefit, please refer to fatwa 84608.
If she agrees to live with her mother-in-law or serve her out of her own free will, then there is no harm in that. The same applies if she agrees that her husband be absent from her for a year or years, otherwise the basic principle is that she has the right upon her husband not to be absent from her more than six months without her consent, as has been clarified in fataawa 88642 and 84073.
The traditions that are against Islamic law are not taken into account.
Allaah knows best.