My friend, you are not going to like my answer. Here it is: You teach people how to treat you. Listen to your words "I am not allowed...." You are a grown man. It's not your wife's fault that you "fear her anger and confrontation."
Whereas you are right that you should have a voice, but you silenced yourself, my friend.
My advice- tell your wife that you are unhappy and want to get some marriage counseling. If she refuses, move out until she agrees. Then you two need to NEGOTIATE.
Her kids are grown, you can't "parent" them now. However, you can have boundaries in the home you support. Negotiate boundaries.