Why does he have my new number saved after our fight. and acting strange?

We broke. Mostly it was due to his lack of interest. There was just one time when I rang him with my new number. Then he had already broken up with me. I assumed he would have missed it since that wasn't my official contact.

Fast forward several months, he began to talk. I said 'Call' and typed my number since too lazy to text all day. Then I deleted it before he saw. But to my surprise he called. I didn't pick. Returned the call days later and asked 'Who' to which he angrily said 'Wrong number'.

Met at library by accident and he came, sat next to me for a whole day. I didn't talk. When I didn't pay 2 fucks, he began shaking legs that the entire bench shook. Then he searched my social profile (I got notification). Then heard him say 'she used to talk once' to his friend about me. Last, he kept his book on the chair between us. I left and I saw him following me. I stopped to let him pass then.

Anyways last day I texted him to refer me to an opening with 'Can you refer me to any openings or HR' to which he responded. It thought he would ask 'who' but he responded positively.

Why does he have my new number saved after our fight. and acting strange?
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