All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There is no doubt that the husband is the first responsible of his wife and children. So, he should guide them to the right path and educate them according to the good that would benefit them in their religion as well as their worldly affairs.
Allah Says (what means): {O you who have believed, protect yourselves and your families from a Fire whose fuel is people and stones, over which are [appointed] angels, harsh and severe; they do not disobey Allah in what He commands them but do what they are commanded.} [Quran 66:6]
Needless to say that adhering to the Sharee’ah obligations is the key to happiness in this life and the Hereafter. It is known in the Sharee’ah that Hijaab is among the most emphatic obligations of Islam and that giving it up is a major sin.
Allah Says (what means):
• {O Prophet, tell your wives and your daughters and the women of the believers to bring down over themselves [part] of their outer garments. That is more suitable that they will be known and not be abused. And ever is Allah Forgiving and Merciful.} [Quran 33:59]
• {…and not to reveal their adornment except to their husbands, their fathers, their husband's fathers, …} [Quran 24:21]
• {… and do not display yourselves as [was] the display of the former times of ignorance. And establish prayer and give Zakah and obey Allah and His Messenger…} [Quran 33:33].
Moreover, dear brother, your marrying a woman that does not adhere to the Islamic obligations is a mistake in the first place, and it is contradictory to the Prophetic orientations in this respect. Actually, the Prophet guided the men to choose in the marriage the pious and religious woman. Imams Al-Bukhaari and Muslim reported that the Prophet said: “Choose the religious one (woman) you will prosper.”
Since you already married this woman, we advice you to seek the Help of Allah asking Him to guide her to the right path. You should also tell her the Sharee’ah rulings in a soft way. Be kind with her, patient, and calm. But let her understand very clearly that you would not drop any of the Orders of Allah under any circumstances. We advise you also to get as close as you can to her and show her your readiness to compromise in everything except religious matters. If you can ask some righteous sisters to talk to her and to try to convince her to abide by the Orders of Allah, then do that. If all that does not have any good impact, then she is considered a disobedient wife.
For more benefit on the steps to be followed by the husband in dealing with a disobedient wife, please refer to Fataawa 89480, 84120, 357901, 85402, 400900, and 83244.
Allah knows best.