1) no 498A case is maintainable . it can only be filed by wife not a mistress
2) section 498A reads as under
498A. Husband or relative of husband of a woman subjecting her to cruelty.
Whoever, being the husband or the relative of the husband of a woman, subjects such woman to cruelty shall be punished with imprisonment for a term which may extend to three years and shall also be liable to fine.
3) you can move HC for quashing the complaint