I just realised what my mistake was. It wasn't my fault when my relationship ended, when I could see it getting worse, I wasn't at fault. I was ,but at fault, when I expected him to understand what I was feeling at that time. This isn't a taunt to him, or anything else to be taken that way, but an actual realisation.
How do you expect anybody, no matter how close they are to you, to realise why you feel what you feel, how do you expect them to say exactly what you want to hear, how do you want them to not talk to the people you don't like,how do you expect them to know everything that is going on in your mind? How do you expect them to empathise with you, when you aren't able to make sure of your own feelings, your thoughts, your goals, your reasons, your decisions? They can't understand you, not because they aren't able enough, but because you cannot do that too! You can't make sense of what you feel and how you feel, why you do that you always hate later, but you still do it anyway, you can't keep track of your moods, you can't make everything right, you can't think and be positive all the time.
Then how on earth did you expect them, just a person as you are, so entirely different in mentality and conditioning, to make you happy, to be responsible for your emotions, to be in charge of your failures? And is it actually their responsibility to make sure they fulfill all your expectations? They are with you simply because they made a choice. They can make another choice and not want to be with you. And guess what, the next choice is yours, to either brood over their loss, and overthink about why they left you, or do the wise thing which you know you should do.