What are the obligatory roles of a wife?

A wife has a right upon her husband just as he has a right upon her. The rulings of Islamic law are not to be handled by seeking hadiths (Prophetic traditions) and legal evidences to put one in the right and holds the other accountable. This makes religion a means of pressuring one's spouse into submitting to the wishes of the other while disregarding one's duties.

Marital life is based on tranquility, mercy, love, and mutual consideration of feelings more than on demanding rights. The true understanding of marital life and the noble manners that the Messenger of God (peace and blessings be upon him) taught us is that a wife is required to be mindful of God Almighty with regards to her husband. She must know that treating her husband with kindness and patience is one of things that will lead her to paradise. A wife should also know that she is the lawful means for her husband’s sexual gratification and she must therefore not refuse him sex. It is also impermissible to make her husband feel that he comes at the end of her priorities.

On the other hand, a husband is to take into consideration his wife's weakness and hard work all day doing household chores and attending to the children's needs. He must be merciful to his wife and not burden her with more than she can bear. Through such mutual sincere feelings, spouses can fulfill their obligations and duties towards each other as prescribed by God Almighty. It is erroneous to drag unrest deliberately into martial life. God Almighty says, "He gives wisdom to whom He wills, and whoever has been given wisdom has certainly been given much good" (Quran 2:296).
And God Almighty knows best.