Am I right to think this way?

I used to be mad at my distant cousin for spreading a rumor about me to my brother who's living in the same house as me, and thereby messing up my relationship with him. But now I think the person I should be mad at is my brother, because he believed it and accused me of something I didn't do, when he never once came and talked to me about it. I couldn't care less about my cousin, I hardly see her, but I'm thinking I should expect better from my brother?