Since India does not have a law on marital rape, even If a woman’s husband has sexual intercourse with her without her consent, he cannot be prosecuted for rape. However, excessive and unreasonable demands for sex, or demands for unnatural sex have been considered forms of cruelty and may entitle a woman to a divorce.
If a woman is judicially separated, her husband cannot have sexual intercourse with her without her consent. If he does, he can be prosecuted under section 376-A of the IPC.
Note that consent under pressure ( e.g. because of threats to injure or to stop paying maintenance) is not considered valid.