Section 13M. (a) Whoever commits an assault or assault and battery on a family or household member shall be punished by imprisonment in the house of correction for not more than 21/2 years or by a fine of not more than $5,000, or both such fine and imprisonment.
(b) Whoever is convicted of a second or subsequent offense of assault or assault and battery on a family or household member shall be punished by imprisonment in the house of correction for not more than 21/2 years or by imprisonment in the state prison for not more than 5 years.
(c) For the purposes of this section, ''family or household member'' shall mean persons who (i) are or were married to one another, (ii) have a child in common regardless of whether they have ever married or lived together or (iii) are or have been in a substantive dating or engagement relationship; provided, that the trier of fact shall determine whether a relationship is substantive by considering the following factors: the length of time of the relationship; the type of relationship; the frequency of interaction between the parties; whether the relationship was terminated by either person; and the length of time elapsed since the termination of the relationship.
(d) For any violation of this section, or as a condition of a continuance without a finding, the court shall order the defendant to complete a certified batterer's intervention program unless, upon good cause shown, the court issues specific written findings describing the reasons that batterer's intervention should not be ordered or unless the batterer's intervention program determines that the defendant is not suitable for intervention.