You can state that as your wishes, but what happens after you've gone may be a different matter. Why don't you leave it divided equally between the three of them, on condition that your children allow your wife to live in the house for as long as she wishes, then when she wants to sell, all three get a share? She would also need to make it clear in HER will that her estate from the house only includes that third. I'm not an expert so will be interested if others feel that this is feasible.