Re: I don't know what to do, 4yo leaving the house
We installed a slide lock towards the top of our front door.. you know the kind that is similar to what is on a bathroom stall door.
Kids couldn't reach it, even if they stood on a chair. Problem solved. You would just need to make sure your husband wakes you up in the morning so that you can lock it after he leaves.
Your other option would be to put a lock on your DDs bedroom door to keep her in until you're awake.