Help My Ex Is Crazy

My ex is a narcissist who emotionally and sometimes physically hurts women and there’s nothing to do about it and it’s starting to truly deep down bother me a lot. I was the first to truly experience his mood swings and insecurities and lies and him yelling at me and making me feel insecure and dependent on him until I fought back (not physically) and suddenly I was the bad guy. He literally spit on me and at times guilted me into sex (I was a Virgin when we got together) and told me that was the only time he felt like I loved him. He has done this to multiple other girls now. He has taken their virginities and screamed at them and punched things and lied about me saying I tried to stab him (100% false) and became physically abusive to his most recent ex and also guilted her into sex a lot and blamed her for his depression and insecurities and for not being able to quit smoking, etc. and threatened to leak her nude photos on snapchat today... all he’s gonna do is go to another sweet innocent girl next and do the same stuff and give her a twisted view of love. He is toxic and his mother knows these things he does and defends him constantly. He needs to be stopped. Any advice would be amazing. I’m pretty sure he has actual mental problems in some way that haven’t been evaluated or dealt with... I don’t want him to continue this cycle of hurting girls and making them question their self worth.