How do you break up with a boyfriend you don't like anymore if you've only been going out with him for a month and this is the second time you've been together?

Maybe this will give you a little insight: "I need to talk to you about something that's been on my mind for a while. When we were going together the first time, toward the end of our relationship, I started to lose sight of what it was that kept us together. Deep down, I really wanted to love you because you were so loveable. But now, I have a better perspective on my feelings, and I see that what I thought was love, really wasn't. Getting back together with you this time, I really felt that I needed you in my life because all those old feelings came back, and I thought that I really loved you. It turns out that my feelings the first time were right. As much as I want us to be together, and to love you totally, I can't because I don't. I have changed, and you have too. It isn't fair to you; it isn't fair to me for us to stay together. So this time, we are done."