AITA for choosing my brother over my marriage?

My parents divorced when I was 3, and went into separate marriages. I had a rough childhood being split between two different households, it was really messy and made me not want children at all. When I was 20, my parents reconciled after their second marriages had ended and had my brother soon after. I had already been dating my now-wife for a year, and we were eventually married, she agreed with me about not wanting kids.Five years later and my brother is now 6, and all is not well in my parents marriage. My mother had an unexpected hard attack and died. My father did not take it well, and drank himself to death. Obviously my family is morning, and I've been trying to find a home for my brother, none of my half-siblings want him.The only other option would be for him to go into foster care, and I'm not going to let that happen. I told my wife that I was going to become his guardian, and that she did not have to stick around in this marriage if she didn't want to. She did not take it well and is furious that I would choose my brother over her. I doubt my marriage will survive, but I can't let my brother go into foster care. via /r/AmItheAsshole http://bit.ly/2JdgyTw