(a) This article applies to the prosecution of an offense under § 36.05, Penal Code, in which:
(1) the underlying official proceeding involved family violence, as defined by § 71.004, Family Code; or
(2) the actor is alleged to have violated § 36.05, Penal Code, by committing an act of family violence against a witness or prospective witness.
(b) In the prosecution of an offense described by Subsection (a), subject to the Texas Rules of Evidence or other applicable law, each party may offer testimony or other evidence of all relevant facts and circumstances that would assist the trier of fact in determining whether the actor’s conduct coerced the witness or prospective witness, including the nature of the relationship between the actor and the witness or prospective witness.