What is the word that we use to call a father who is the main earner in the family?
Solution 1:
You can call such a person (m/f) a breadwinner:
a person who earns money to support a family
(source: Merriam-Webster)
Solution 2:
You can also use the idiomatic expression: he who brings home the bacon:
to earn money to live on:
- If Jo is at home looking after the children, someone needs to bring home the bacon.
(Cambridge Dictionary of American Idioms)