A more thorough explanation:

Domestic partners are two people who are in a committed relationship that is legally recognized as being similar to marriage. This commitment is usually made through a civil union. People may choose to become domestic partners because they cannot get married or because they do not want to. By entering into a civil union, they can receive benefits and protections that are similar to those given to married couples.

For example, if a same-sex couple lives in a state that does not allow them to get married, they may choose to become domestic partners instead. This would give them some of the same legal rights and protections that married couples have, such as the ability to make medical decisions for each other and to inherit property from each other.

It is important to note that domestic partnerships have become less common since the Supreme Court ruled in 2015 that same-sex marriage is a constitutional right. However, some states still allow domestic partnerships, and all states are required to recognize them if they were created in another state.

Overall, domestic partnerships are a way for couples to formalize their commitment to each other and to receive legal protections that are similar to those given to married couples.