This sounds a bit similar in ways to my situation.
So I was seeing someone very briefly in 2017/2018.. it was awful, he was a total control freak and it was always his way or no way so it all came to an end and he left me alone. However, when he realised I wasn't going to run after him - he started to bombard me going down the super friendly route or then when he got no response going down the feel sorry for him route. I eventually met my now partner in May 2018 and as soon as my 'ex' if you could call him that so lets call him 'Pete' (not his real name) - As soon as Pete found out well he started to really increase the calls/texts. It would be hundreds of texts a day, essays about how much of a slut I was, then essays about how much he loved me, then essays about how he would kill himself if I didn't get in touch because he had nobody, then essays about how I was a fat mess. He decided to contact my boyfriend through all forms of social media, he contacted my boyfriends mum and called her a slut. He contacted members of my family including my own brother who is super Christian and pretended he wanted to turn good living and go to church with him! He told me he was ending his life so I called the police who went and visited his address to check on him where they found he was absolutely fine. I lost my best friend to suicide 10yrs ago so for him to pretend he was going to take his life was just horrible. He would create fake emails, fake twitter accounts, fake instagram etc and send messages through there. I went to the police numerous times but each time it would be ''Change your number'' ''remove all your social media'' ''we can't say anything to him until he has actually done something'' - My mental health took such a nose dive. I was constantly looking over my shoulder. Telling my boyfriend not to post where we were etc. He manipulated a few 'friends' of mine too and fed them lies but thankfully most people saw through it all because of the hundreds and hundreds of screenshots of abuse I had. It's been 4 years now and I still live rent free in his head, I've been told he still watches my social media like if I change my profile pic or if I post on twitter which is my only public social media - I don't post anything super personal on there and I certainly don't post my whereabouts until I am not actually there anymore such as talking about a good restaurant I've been or something. He hasn't contacted me in a few weeks but I don't think he has gone for good - Usually find when he is quiet he has got someone new and usually when it doesn't work out he comes back and tries to play pity party with me via email but I ignore him each and every time even though I am so angry I have allowed it for so long. I think its absolutely vile and disgusting with some of the things he has said to me over the years and just expects me to be ok with it. I remember telling him 4 years ago how hurtful he was being, how his words were just disgusting but he ignored me and continued. I shouldn't have to change my number, I shouldn't have to live my life like a hermit but slowly and surely I am gaining confidence again.
Stay strong OP, don't give in to him and give him the attention he obviously craves cause each time you do he thinks its ok to keep contacting you. Narcissist is all he is.
I am so sorry you are going through this but I hope things get a bit better for you just try & nip it in the bud now, don't converse with him in any way shape or form xx