Dreaming about what it means to kill my wife, although I have only had this dream once, I can't let it go, and it feels very realistic.

The dream wife is not necessarily your real wife. From the dream point of view, the wife in the dream is more likely to be a part with female characteristics.

You may be dissatisfied with yourself in your dreams. Maybe you don't like that part of your wife's similar characteristics and the way you handle things, so you want this part of your characteristics to disappear from yourself.

The wife in the dream died in the cradle in a red coat. This detail is worth noting. I think it has more to do with your childhood memories. You can try to think along the lines I mentioned. What does this scene remind you of Is it related to your childhood experience?

But in any case, this dream has little to do with your wife, only with you.