I get the impression at times that some people refer to the woman of the house as the "boss" for two reasons:
1. Husband/bf/partner respects wife's knowledge/opinion/feelings, etc., so they don't mind letting her have her way, or give in easily.

DH and I were in Lowe's recently, and finding ourselves in the appliance section, studying the ovens/stoves. We're going to need to replace ours at some point since it's kinda old and I pointed out a gas oven and range I really liked. "What's wrong with electric?" Me: "I'm more comfortable using gas ranges and being the main cook for the family, I'd use it more than you." DH: "Good point, okay, pick whatever you like."
2. It's coming from the sort of person who would call a woman a word that rhymes with witch because she hurt his poor widdle ego by not letting him be lord and master of his house.