"Wears the trousers" is a colloquial expression that means to have the dominant role in a relationship, usually within a romantic context. However, there are many other phrases that can be used to convey a similar meaning. One alternative is to say someone "wears the pants," meaning they are in control or have a dominant position. Other synonyms include "takes charge," "calls the shots," "wears the crown," or simply saying someone has "the upper hand." Each of these phrases conveys a sense of power or control, and can be used in a variety of contexts beyond just romantic relationships.