Moving forward you’ll handle it better. Firm consistency while being gentle with letting him down. Tell him you have to end the relationship and no amount of his texting will change your mind. You are sorry for having given him any mixed messages, but you do not feel the same way about him as he does for you. Then don’t respond. Break his way of contacting you. I hope he doesn’t really become a dangerous stalker.

I’ve had to go up against some of the most obnoxious, pushy people and stand my ground. I found the only thing that works is firm, consistent resistance and then ignore. They all eventually gave up. Please be careful, though. His level of emotional disturbance is concerning.