Let me offer you another perspective: You say your husband loves you and you are good together. You also say that your husband warned you years ago that his brother is a bad person. It looks to me like your husband has given up trying to change his brother — and probably for good reason. It may be that not “defending” you was the best defense of all.
For you to hold onto a grudge against your husband for two years will doom your marriage. You can’t continue feeling “alone”. He can’t sustain feeling like he is failing some kind of “test”. It’s a wonder to me that the two of you have been able to live together for two years with this kind of tension between you.
Here’s what is real: Your husband hasn’t found a way to influence his brother to give up his anger or to get treatment for it. You can’t change his brother either — and you can’t change your husband’s relationship with his brother. Your husband doesn’t see a way to manage his brother differently or he would have done it long ago.
From what you shared, I think nothing good would have come from “defending” you on the ski trip. His brother would have only escalated. You had to make the drive home together so it may have been wise for your husband to do what he always does — ignore and placate, this time to make sure you had a ride home.
The problem for you is not that your husband didn’t leap to your defense. The problem is that you and your husband don’t have a clear mutual understanding about why maintaining some kind of relationship with brother is important and how to manage his anger issues and aggression.
I can’t offer a solution here. I just don’t have enough information. You and your husband need the guidance and support of a family therapist to get to the bottom of what goes on and to come up with ways to deal with brother — together. The situation is too painful for you both to carry on as you have done.
Please. Ask your husband to go with you to some sessions with a licensed family therapist. If he won’t go, go yourself. Often one partner has to take the lead before the other person feels comfortable joining in. You need expert help. Otherwise, I see a divorce in the making.
I wish you all well.