You showed him one kindness when you're both kids, and since then he's been following you like a puppy. He's very loyal, as he saw you as one of people he can trust.

But his behaviour is too obsessive and overprotective of you, because Jeremy want your affection and attention to be directed to him and him alone. He'll do anything in his power to limiting you to anyone else beside him, even from your own family.

"I forbid you to give your attention to anyone else but me."