Age at first marriage has risen substantially and birth rates are at a record low; people are spending more time in relationships that, by comparison, have fewer emotional, financial, and legal commitments. Little research has examined intimate partner violence (IPV) prevalence in current and former adult (vs. adolescent) dating relationships. Such information is relevant to federal firearms policies that are based on the nature of an intimate relationship. We examined assaultive behaviors by the type and status of the relationship – current spouse, former spouse, current boyfriend or girlfriend, and former boyfriend or girlfriend – in 31,206 IPV incidents responded to by Philadelphia police in 2013. Over 80% of the IPV incidents involved individuals in non-marital relationships. Incidents involving current boyfriends or girlfriends had the highest percentage of violent behaviors (e.g., punch, strangle). They also were more likely than current spouses to use bodily weapons (hands, fists, or feet) or non-gun weapons (knives, bats, etc.) (AOR = 1.19 and 1.43, respectively), to injure their victims (AOR = 1.37), and to be arrested (AOR = 1.46). Former unmarried partners had the highest odds of stalking their intimate (AOR = 3.37) and violating a restraining order (AOR = 2.61). Gun use was similar across relationship type. A growing portion of the population is not protected by federal policies designed to keep guns out of the hands of abusers. Current boyfriends and girlfriends are a risk to their intimates. Federal data collection practices and firearm policies merit updating to more fully take into account dating, same-sex marriage, and other partnerships.