Don't rely on a will and don't rely on good will both can change.
If a wife gets cut out of a will she can challenge the will and get a judgment, a husband cannot leave his wife with nothing, so that is the fallback.
A friend of mine has a similar problem, his second marriage, 3 children by the first. They have been together 30 yrs, married for 18, he has dementure and is disposing of all his assets and giving the cash away, his son has power of attorney so she can do nothing.
His avowed intention is to leave her with nothing " I picked her up in a bar I've given her a good life now she can go back to the bar".
So she is having to divorce him to get a share of the house.
An extreme example but it does happen.