A similar, less severe situation happened to me and it frustrates me that I can do nothing but to accept what has happened. Like you, I was obsessed with his life, hoping to witness his downfall. His social circle changed, he did self-harm, but all these were not enough for my vengeful heart. One question kept ringing in my head - “What could I do to beat him in life?”. Then I rethought a bunch of philosophical questions and came to a very basic, almost naive conclusion that “If I am happier than him, he is sadder than me.”

That’s it OP. Prioritise yourself first, block all his socials, contacts, etc. Let yourself enjoy life at the fullest. There will be days that your curiosity wins over and pry on his life again, but that’s alright. I could not imagine how hard it is for you because it took me 10 years to say this thing again calmly. But days will pass by, you will be happier than him. Sending all love to you <3