Cruelty by a spouse is treated through the same criminal provision, whichever spouse commits it.
RealityBharatiya Nyaya Sanhita (BNS) sections 85 and 86 — carrying forward the earlier IPC section 498A — specifically criminalise cruelty by a husband or his relatives against a woman. "Cruelty" is defined to include conduct likely to drive a woman to suicide or grave injury, and harassment linked to unlawful demands for property or valuable security.
What this does not mean: That harmful conduct by a wife against a husband is lawful. General offences covering hurt, criminal intimidation, defamation and similar conduct can still apply to that behaviour. What is sex-specific is this particular matrimonial-cruelty offence: it is defined as cruelty by a husband/his relatives against a wife, not as a spouse-neutral offence.