ok allow me help with this question as i am a police officer, I will give you the truth under New Jersey law, but most likey applies to other states.

you & your wife are asleep, you here someone in your house, she calls 911, you grab your firearm, you meet this dirt bag on your steps, he's unarmed, but you point your gun towards him, tell him to stop, but keeps coming towards you, you CAN NOT fire your firearm, he's unarmed, makes no sense to me as a cop, but thats the law.

same set up, but this time he as a gun, yes you CAN fire your gun, but always aim for center mass. if this dirt bag runs after you fire, falls and dies on your front lawn, DON NOT touch him, during the investigation they will see that you shot him on your steps, he turned and ran, died in the yard.

lets say GOD forbid, your wife or you are home alone, this dirt bag breaks in he's 6'4" 275lbs., your wife is 5'3" 110lbs, your 5'7" 170lbs. he attacks one of you but is unarmed, because of the large difference in body size and weight you both may use Deadly FORCE, because you can or will get serious bodily injure or serious bodly harm.

what it boils down to is that the investigating officers and others will look at the TOTALITY OF THE CIRCUMSTANCES

i hope this will help you and your family, and hoping that no one ever has to go thru this.