Getting revenge. Is it worth it?

I am having feelings I have never had before. I am not a vindictive person, but after years of standing beside my bf and helping him with his drug addiction and he relapsed two weeks ago and I kicked him out. I am going back to college full time and he was paying the bills. He told me that he would take care of everything and stand beside me 100%. So I quit my job and went back to college. He then decided to start doing his drugs again and I could not go through that hell again so I booted him. The day I kicked him out he went to the bank and put a stop on the checks he wrote to pay for the bills. I am so ANGRY. I never did anything to hurt him. I have to children 13 and 15 and I cannot have drugs around my kids. What kind of person does that. He told me over and over again that I was the best thing that ever happened to him and I am the only one that ever tried to help him in his whole life. How could he be so mean and hateful. I just want to mess up his life.