Unless one has been charged with domestic violence or a related crime, it's easy to imagine the charges only affect certain types of people and households. Contrary to popular belief, charges of domestic violence don't just affect those who are married or living with a current or former romantic partner.
The state of Washington defines domestic violence as various types of harm or assault inflicted by one "family or household member" upon another. However, there are various individuals that the state describes as family or household members. These include spouses, of course, but also former spouses, adults related either by blood or by marriage, current and former domestic partners and adults who are currently living together or who have shared a residence in the past. The list also includes individuals who have a child together; these individuals do not have to have ever been married or lived together in the past.