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Why is my ex boyfriend doing this?

So me and my ex boyfriend had a very very messy breakup. He engaged in emotional, verbal and physical abuse. Eventually, we met up one time to discuss it and he said he regretted everything, so I felt peace. Since that day, I stopped contacting him. However, I was still in contact with his cousin and we were extremely close, but kept it a secret. My exes dad then passed away a week after I had met up with him, and so I tried reaching out to him to give him my condolences. A week after his dad passed, I had found out he was now very close to this girl I hated. Me and the girl then had another fight and my ex got involved and verbally tried to humiliate me in front of her and her friends. We both said awful things to eachother and it turned into another argument between us. After this day, my ex would get his friends to harass and bully me near enough everyday. This went on for about 2 months. Then my exes cousin was forced to cut me off. One of his friends then found out that I'm now in a very happy relationship with a man that my ex hates. During this time, my ex added my little sister on socials. I messaged one of the boys my ex sent to harass me and told him to tell my ex never to add my little sister again. My ex and his friend denied he did. I then messaged my ex about the harassment from his friends and the calls from them and he denied it all. He then proceeded to block me and my little sister. The harassment still continued. Then one day my ex requested to play a game with me on an app we both used to play and he sent me a gift on the app aswell. I was so confused after he begged me to leave him alone etc, why he would do that. Then my boyfriend even tried contacting him to leave me alone after he saw how this was all affecting me, but my ex never added him back. My cousin even had to step in, as I no longer wanted any direct contact with him, to which he said this (see pictures below). However, he never once blocked my cousin as he did my bestfriend,
Why is my ex boyfriend doing this?
Why is my ex boyfriend doing this?
Why is my ex boyfriend doing this?
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my sister, my mother and me, from months prior. Since that interaction, everything eventually calmed down. Until I received another private number phone call from one of his friends. Then again, silence for weeks. Until lastly, my ex added my male cousin on a PlayStation game last night. I just can't understand why he's doing all of this after going around saying im psycho and how he wants nothing to do with me anymore. I just don't understand what he wants from me.
Why is my ex boyfriend doing this?
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