The concept of 'marriage' among Muslims from the very beginning itself (is) regarded as a contract. Muslim marriage has been defined as a civil contract for the purpose of legalizing sexual intercourse and procreation of children. It is not a sacrament but a contract, though solemnized generally with the recitation of certain verses from the Quran. Muslim law does not prescribe any religious service essential for solemnization. Justice Krishna Iyer in 'Islamic Law in Modern India' considered the concept of Muslim marriage and stated that "in its legal connotation, Muslim marriage is essentially a contract, though marriage as a social institution is regarded solemn all over the civilized world, including the Muslims.
A Husband may divorce in the following manner-
1. Talaq: which is release from the marriage tie immediately or eventually.
2. Ila: where a husband of sound mind takes a vow that he will abstain from all relationship from his wife.
3. Zihar: where husband sane and adult compares his wife to his mother or any other female within the prohibited degrees.
Are you sunni or Shia?Sunnis, talaaq may be express, implied, contingent constructive or even delegated. The Shias recognize only the express and the delegated forms of talaaq.
Conditions for a valid talaaq:
1.) Capacity: Every Muslim husband of sound mind, who has attained the age of puberty, is competent to pronounce talaaq. It is not necessary for him to give any reason for his pronouncement. A husband who is minor or of unsound mind cannot pronounce it. Talaaq by a minor or of a person of unsound mind is void and ineffective. However, if a husband is lunatic then talaaq pronounced by him during “lucid interval” is valid. The guardian cannot pronounce talaaq on behalf of a minor husband. When insane husband has no guardian, the Qazi or a judge has the right to dissolve the marriage in the interest of such a husband.
2.) Free Consent: Except under Hanafi law, the consent of the husband in pronouncing talaaq must be a free consent. Under Hanafi law, a talaaq, pronounced under compulsion, coercion, undue influence, fraud and voluntary intoxication etc., is valid and dissolves the marriage.
Involuntary intoxication: Talaaq pronounced under forced or involuntary intoxication is void even under the Hanafi law.
Shia law: Under the Shia law (and also under other schools of Sunnis) a talaaq pronounced under compulsion, coercion, undue influence, fraud, or voluntary intoxication is void and ineffective.
3.) Formalities: According to Sunni law, a talaaq, may be oral or in writing. It may be simply uttered by the husband or he may write a Talaaqnama. No specific formula or use of any particular word is required to constitute a valid talaaq. Any expression which clearly indicates the husband’s desire to break the marriage is sufficient. It need not be made in the presence of the witnesses.
According to Shias, talaaq, must be pronounced orally, except where the husband is unable to speak. If the husband can speak but gives it in writing, the talaaq, is void under Shia law. Here talaaq must be pronounced in the presence of two witnesses.
4.) Express words: The words of talaaq must clearly indicate the husband’s intention to dissolve the marriage. If the pronouncement is not express and is ambiguous then it is absolutely necessary to prove that the husband clearly intends to dissolve the marriage.
Express Talaaq (by husband):
When clear and unequivocal words, such as “I have divorced thee” are uttered, the divorce is express. The express talaaq, falls into two categories:
Talaaq-i-sunnat has two forms:
1. Talaaq-i-ahasan (Most approved)
2. Talaaq-i-hasan (Less approved).
Talaaq-i-sunnat is considered to be in accordance with the dictats of Prophet Mohammad.
So in your case if you want to divorce then the above said facts kept in mind. You can file case before the court of law under the ground cruelty ; Denial of sex by spouse is cruelty.