WW4: Whether or not you are unreasonable is irrelevant - what matters is that you are not HAPPY.
You are not happy in this relationship. He is not making you happy.
That's the beginning and end of it.
He is not showing commitment, he is stringing you along, he is undermining your relationship with your Mum - (and what right does he have to do that? he is a boyfriend, she isn't his MIL, and if she was he would need to show more respect than issuing an ultimatum!)
He lies to you, he is miserable, he robs you of self esteem....
You are not happy.
Don't wait for him to come back and tell you why HE isn't happy and why it is all your fault, tell him that you are finishing because you are not happy with the relationship and not happy with him.
Then BLOCK HIM and do not engage in ANY discussion about how it is all your fault and him demanding that you try and justify your decision about him.
A better life awaits you, but not while this is dragging your life down.