Should I tell someone I cheated with the boyfriend?

I was married to someone, however it ended in divorce. We tried to work it out numerous times but we failed. 2 months after we split up for the last time we got engaged to someone. The whole time we were split we “got together”. I knew he was going out with someone, but I still loved him. I still hoped we’d get back together. Even after he got engaged we still slept together. I know it’s not right, but I loved him so much I still had hope that we would get back together. I sent his girlfriend letters telling her that he was cheating on her. Of course I didn’t put my name on them. I even sent his sister a email stating that her brother was cheating on his girlfriend. My ex has no idea it was me sending this stuff. He is getting the police involved, stating that he fears for his life. No one was ever threatened in any way. I should mention he’s a police officer. I now feel horrible for sending the letters and emails. I honestly don’t want anyone to know about our affair. My ex and his girlfriend has since gotten married and I will not send another letter. I didn’t want him to get married, but I will not break up the marriage. I feel horrible for what I’ve done. I’m not sure what to do next. And people, I know it’s wrong to cheat with someone’s boyfriend, but I really did love him and really hoped we would get back together. I know it’s crazy but he still felt like mine. I don’t know if I should tell him it was me sending the letters and emails, should I?