The Beta Theory.
The Beta Theory determines which person involved within a relationship with another person (Male=female, female=Male, Male=male male=Male, Female=female, female=Female, etc.) is the more dominant partner in the relationship. The Beta partner will exemplify a more amiable feeling and a higher level of a more loving nature toward their partner, a contrast from their partner's level of same feelings. Not to be confused with the Alpha Male, as this theory not only determines the #2, but is also applicable to anyone in any type of relationship: monogamous or otherwise(and sometimes incest).
This theory was inspired by Krzysztof Kieslowski's film White, Reefer (as the young kids say), DunkAroos, and the Prince album "Come".