He says that since his work is so long that he would not contribute to chores at all. If I take on the chores, he feels that we will be equal.

I don't see how it could be equal or fair.

It's not equal because you work and study outside the home, too. You also pay bills. I could see chores being proportional based on hours work and monetary contributions, but the key word there is proportional. You wouldn't be saddled with school, work, and 100% of the chores. He's picked a distribution that only makes sense from the perspective of a person who doesn't want to do chores.

It's not fair because - and this is important - doing some chores encourages courteous and responsible behavior. If I have to clean the kitchen this week, I'm less likely to trash it all week when I cook. Chores are an incentive to respect our environment and partner's needs. Someone who never has to contribute to the maintenance of the household will soon take it for granted.

I just feel so mentally and emotional overworked which I have expressed but he says that any other way is unfair to him and that I am trying to manipulate him into doing more work.

The opposite is closer to the truth. If he makes some mess, he should do some cleaning. He's manipulating you into thinking that ZERO cleaning if you work full-time is normal.

Even in situations with a stay-at-home parent, the working parent still does some work in the evenings and on weekends. Hell, my SO is an attorney who frequently works 60 hours a week and he still scoops the litter box, vacuums up the cat litter, does his own laundry, grocery shops with me, and grills/cooks a couple nights a week. Why? Because he's an adult and knows that adult responsibilities don't end when work is over.

And you know what? If you moved out, your boyfriend would figure out a way to cook his own dinner, vacuum his own floor, clean his own bathroom. He has the time. He just doesn't want to because he's tired. Well, we all are, you included.

Stand up for yourself. You can start by just refusing to clean up after him until he figures out that the household is a joint responsibility even if one person does more than the other.