How to handle a psycho ex????? HELP

Okay. So, to beginning I was in another relationship with *chad and was taking a break and got with *brad. Well long story short after a while I tried ending it with brad bc I was just trying to rebound from Chad. I ended up being with chad again eventually and it's honestly the best we've ever been. However, little brad over here is driving me insane and he's threatening to post nude pictures of me online or kill himself if I stop seeing and talking to him. He says I'm the love of his life and cries all the time about how he can't live without me. I don't wanna tell chad these things bc he knows brad and they work next door to each other so that would only make things more complicated in my mind.. I'm just not sure how to tell brad that I am done. I've literally told him in every way possible that he's going to be fine and I just want to be left alone. But he still persists and will not take no for an answer...... any thoughts or suggestions on what to do would be highly appreciated. Thanks