(a) A husband and wife shall be competent but shall not be compellable to give evidence in any criminal proceeding for or against each other.
(b) The privilege created by subsection (a) of this Code section or by corresponding privileges in paragraph (1) of subsection (a) of Code Section 24-5-501 or subsection (a) of Code Section 24-5-505 shall not apply in proceedings in which:
(1) The husband or wife is charged with a crime against the person of a child under the age of 18, but such husband or wife shall be compellable to give evidence only on the specific act for which the
accused is charged;
(2) The husband or wife is charged with a crime against his or her
spouse;
(3) The husband or wife is charged with causing physical damage to property belonging to the husband and wife or to their separate
property; or
(4) The alleged crime against his or her current spouse occurred prior to the lawful marriage of the husband and wife.