"I'm sure it was a big part, whether you can see that or not," James said, softly. "It took from you what you needed to move past it. You never had the chance to come to terms with what had happened."
James kissed Sirius' forehead. "Are you blaming Peter now? Because, love, it sounds to me like you're blaming yourself. I don't believe in that pansy psychology stuff, but maybe you hate him so much because it's easier than thinking that it's your fault."
He slid down, so he could look Sirius in the eyes. "It's not your fault. You weren't the only one who didn't trust Remus. Dumbledore, James, Lily, they all agreed, and their opinion was more important. In the end, James and Lily made the choice. They opted for Peter. I'm not saying that they are to blame, but I am saying that you aren't to blame. A choice was made, and the wrong person was trusted. No one can be blamed for that."