You should file DV case and seek maintenance from your husband. if your mother in law can help you then you can live in your matrimonial home and try to settle this issue amicably. In muslim law wife has limited recourse regarding matrimonial relief so don't give consent to decide divorce under shariyat law. You should profess your religion and manage to live in matrimonial home. living many years shall mount pressure on him to restitute conjugal rights.
Grounds for divorce in special marriage act :-
Subject to the provisions of this Act and to the rules made thereunder, a petition for divorce may be presented to the District Court either by the husband or the wife on the ground that the respondent-
(a) has, after the solemnization of the marriage had voluntary sexual intercourse with any person other than his or her spouse; or
(b) has deserted the petitioner for a continuous period of not less than two years immediately proceeding the presentation of the petition; or
(c) is undergoing a sentence of imprisonment for seven years or more for an offence as defined in the Indian Penal Code (45 of 1860); or
(d) has since the solemnization of the marriage treated the petitioner with cruelty; or
(e) has been incurably of unsound mind, or has been suffering continuously or intermittently from mental disorder of such a kind, and to such an extent that the petitioner cannot reasonably be expected to live with the respondent.
A wife may also present a petitioner for divorce to the District Court on the ground.-
(i) that her husband has, since the solemnization of the marriage, been guilty of rape, sodomy or bestiality;
(ii) that in a suit under Sec. 18 of the Hindus Adoptions and Maintenance Act, 1956 (78 of 1956), or in a proceeding under Sec. 125 of the Code of Criminal Procedure, 1973 (2 of 1974), or under the corresponding Sec. 488 of the Code of Criminal Procedure, 1898 (5 of 1898), a decree or order, as the case may be, has been passed against the husband awarding maintenance to the wife notwithstanding that she was living apart and that since the passing of such decree or order, cohabitation between the parties has not been resumed for one year or upwards.
(2) Subject to the provisions of the Act and to the Rules made thereunder, either party to a marriage, whether solemnized before or after the commencement of the Special Marriage (Amendment) Act, 1970, may present a petition for divorce to the District Court on the ground-
(i) that there has been no resumption of cohabitation as between the parties to the marriage for a period of one year or upwards after the passing of a decree for judicial separation in a proceeding to which they were parties; or
(ii) that there has been no restitution of conjugal rights as between the parties to the marriage for a period of one year or upwards after the passing of a decree for restitution of conjugal rights in a proceeding to which they were parties.