Why does Raskolnikov decide to confess his crime?

In my opinion, he cannot help himself. It has nothing to do with attrition or guilt, but rather has everything to do with wanting his crime to be discovered. He wants to confess, and yet, he doesn't. It's a case of tempting fate. Raskolnikov consistently pushes the envelope... talks to much, exposes himself. None of these things point to a man who wishes his crime to stay a secret.

"I shall have to pull a long face with him too," he thought, with a beating heart, and he turned white, "and do it naturally, too. But the most natural thing would be to do nothing at all. Carefully do nothing at all! No, /carefully/ would not be natural again. . . . Oh, well, we shall see how it turns out. . . . We shall see . . . directly. Is it a good thing to go or not? The butterfly flies to the light. My heart is beating, that's what's bad!"