This is why it’s so hard to have trust in relationships?

My ex and I broke up about a year 1/2 ago and I was very in love with him. The breakup was very hurtful and I wanted to get back together but once he decided he was done he was very stern on his decision. It hurt so much I had to block his number so I could get over him. He messaged me about 4 months later asking to see me and wanted to take me on a date. I still had strong feelings for him but I was still hurt on how quick he gave up on our relationship before and I did not trust him. I tried to maybe take it slow and see how it went but his behavior was still very shady and it hurt too much to keep him in my life. I decided to block his # and social media again and work on moving on instead. It has been about 8 months later and one night he randomly started blowing up my phone demanding that I go meet up with him and hang out with him and how messed up I was for blocking him and never speaking to him again. He was being very persistent and demanding. I told him I was in a relationship with someone new and he did not care. The thing is , I know he is also in a relationship because I unblocked his instagram and seen his profile picture of him and a girl hugging wearing matching Christmas sweaters. He refuses to admit he is now in a relationship and tries to play the victim of how he was so hurt I left him he stayed single the whole time 🤦🏻‍♀️🤦🏻‍♀️. What is wrong with this man and why is he doing this?
This is why it’s so hard to have trust in relationships?
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