This is a typical abusive/manipulative relationship where in my opinion, your boyfriend blames all of his and struggles and yours on you to keep you down and in the place he wants you to be, where he is in charge and you're just the depressed girlfriend, too torn down by his abuse to stand up for your own happiness and walk out the door.
He doesn't love you, he is an angry person, who is attached to you, and by being abusive, you'll feel too low to leave him, which is what he wants because he's ATTACHED. If he loved you, he would listen to what to you've been telling him all this time and try to change accordingly, to keep you happy. It's clear he doesn't care about your happiness and wellbeing and staying with him will be so detrimental to your health, and you could end up in 20 years time, looking back at all of this with the biggest feeling of regret, thinking you've wasted your life on this one man who is so abusive to you, when there are so many other guys out there who would never think to treat their woman the way he treats you, and you'll be so angry that you've missed out on that for so long.
Please do not get engaged or married to this man. You seem like a lovely person, and he is not the right one for you, if he doesn't treat you like the lovely person you are. Think about if a close relative or friend came to you with the same problem. I'm guessing you would advise they leave their relationship. Try and see yourself from a third person perspective, it will help you to escape from any cycle of negative or irrational thoughts about the situation