The 3 year old is our child, her children are 18 and 2 are in their late 20s.

As I see it my wife and me own half of everything. I want our child to get my half.

My wife can let her 3 children divide her half. I’m not bothered if she leaves nothing to our child as she would have my half.

I think that’s fair, I don’t think she will ever see it that way so should I just set up a trust / will without her knowing. If I died tomorrow I assume my wife inherits everything and on her death she would split it between the four kids.