So, let me just concoct a scenario here.
Say we have a happy heterosexual couple Jim and Jill.
Jim is a competent adult man. Let’s say he’s an engineer, or a programmer, or works on HVAC, or whatever. His skills are in fixing things, clever mechanical solutions, and cooking.
Jill is a competent adult woman. Let’s say she’s an MBA and manages a firm. She has strong decision making skills, people management, financial decision making, etc.
There’s nothing un-masculine about Jim, he’s a masculine guy. And there’s nothing un-feminine about Jill, she’s a feminine woman.
Yet because of her skill set, Jill makes the family’s financial decisions, their vacation planning, delegating things that need to be done in the house, etc.
Both make decent income and share the load of raising the kids; they take turns. Jim cooks delicious meals, Jill cleans after since cooking isn’t her best skill.
What’s wrong with this perfectly healthy and plausible picture? What about Jim makes him by default a “head,” when this family doesn’t seem like it needs one?