If you took work at half market rate, what would you do financially? Cut your expenses back to that level for at least 3 months (if not indefinitely), and save like it’s going out of style. That will give you a cushion and the freedom of a few more choices.

In life, unless you can learn to put away a huge pile of cash, people are just going to walk all over you. When you are vulnerable, it sends a signal and they pounce on it. Your boss will stop abusing you the moment he realizes he can't use it to control you anymore.

Save your money. Pick up new skills. Become less dependent on others. Bike instead of driving. Cook all of your own meals. Learn about investing. Get out of debt. Maintain your own vehicles. Plant a garden.

Take literally any step to make yourself more independent and your boss will lose power.