Which one is worse marriage or MBA
You have two separate issues. The first is that you are miserable in the marriage. The second is that you seem to be suffering from depression and feeling powerless.
You need to fix both... First, it is a misconception that single people have to be lonely. Some of the happiest people I know are single and just go out and get what they want from life and take responsibility for their own happiness. No one is going to 'fix' this but you! The world is full of 10 million exciting and wonderful things to do and people to meet, so if you don't want to be lonely, you don't have to be!
When people get into this kind of fix, it usually means you feel powerless and bored and have no sense of direction in your life. So the first thing you need to work on is you! Make a list of things you've always wanted to do... then start doing them, one by one! And if sitting home and being tortured in a bad marriage is preventing you from doing them, then the marriage has to go!
The fact that you see your life as a choice between two negatives (married/miserable and single/lonely) shows that you are indeed depressed! That is how a depressed person thinks, and you need to get treatment for that. A person who is not depressed would think, i'm married/miserable or single/freedom/opportunities. So the world is not painted black, but offering you many chances again and again to go out and get for yourself what you want and need.
Your problem isn't married/miserable vs. single/lonely, it is your passivity and negative attitude towards life... so you need to first work on recognizing that only you can make your life happy, and the difference between an unhappy person and a happy person is their perspective and willingness to get out and get what they want for themselves rather than moping around and thinking they don't have any control over their life at all. You do, and you can be happy.
Studies have shown that people's main problems are they are risk averse... i.e., they'd rather hang onto one penny than tolerate a little risk and discomfort of risking to choose something else that will probably give them 99 pennies! So you're hanging onto your little miserable one penny marriage when there are millions of pennies out there if you recognize that you need to spend that penny to get the 99 pennies, i.e., give up that marriage in order to make yourself available to someone whom you can be happy with, and to avail yourself of the freedom and opportunities that single life offers. When you're single, your time is you own, your choices are your own, and you have infinite opportunities to choose your own path and life, and change it anytime you please. Being married can offer wonderful security and comfort and its own kind of opportunities, but you must indeed consider its constraints and don't have the open ability to do anything you want anytime you please or make yourself available to other people for new relationships because you do have commitments and responsibilities to your partner.
So you must spend that penny (divorce) to get your freedom and more opportunities to do as you please and see as you please. But if you keep doing what you're doing you'll keep getting what you're getting. Where do you see yourself in 2 years or 5 years or 10 years and how will you feel if you are still with him and nothing changes?
Sooner or later you either have to take the risk and leave, or else decide you are so risk averse you will stay in a bad marriage and heap ashes on your head, or else decide to fully commit to fixing your marriage and fixing your bad attitude towards it and him. If you think there is no hope for fixing it, then really, your best alternative is to leave and give yourself more freedom to pursue opportunities that will make you happy. But make sure to get the depression treated, because that colors everythng.