Well it is not as simple as it is. There's a new law formally introduced against adultery. I think it was highlighted during a case where a politician from a welknown party was caught, may be the info was leaked or something like it.
It was specifically mentioned that any kind of favor and even if it's not rape, it's punishable.
Section 497.
โWhoever has sexual intercourse with a person who is and whom he knows, or has reason to believe to be the wife of another man, without the consent or connivance of that man, such sexual intercourse not amounting to the offence of rape, is guilty of the offence of adultery, and shall be punished with imprisonment of either description for a term which may extend to five years, or with fine, or with both. In such case the wife shall not be punishable as an abettor.โ.
Also please read SITA and ITPA via Google. Basically it applies to public places or within 200 yards or something. The defination is vague hence there are grey and debatable areas.