O.C.G.A. § 16-6-19. Adultery.

A married person commits the offense of adultery when he voluntarily has sexual intercourse with a person other than his spouse and, upon conviction thereof, shall be punished as for a misdemeanor.

O.C.G.A. § 16-6-18. Fornication.

An unmarried person commits the offense of fornication when he voluntarily has sexual intercourse with another person and, upon conviction thereof, shall be punished as for a misdemeanor.

O.C.G.A. § 16-6-3. Statutory rape.

(a) A person commits the offense of statutory rape when he or she engages in sexual intercourse with any person under the age of 16 years and not his or her spouse, provided that no conviction shall be had for this offense on the unsupported testimony of the victim.
(b) Except as provided in subsection (c) [...]