Stay dark on anger days or you will start a fight that could set you back weeks. You have to exercise, journal, vent it to a friend, or get it out in IC. It's not fair. But I bet your dad would be happy to listen to a big earful of it. LOL.
If you want to allow him to come and go, and I think there's a good argument for that, make a habit of hiding your laptop or putting on a password before you leave the house. Put your self help books or whatever away where he won't see them. Other than that, who cares if he sees your dirty laundry? He's living his dirty laundry.
How can you leave stuff out on the counter for him to see if you change locks? How can he kiss the turtle or boxer in private if you're there? For all you know, he's laying in your bed feeling awful for a few minutes. Let him.