I feel pretty embarrassed even writing this, but since you all give good advice, I thought I'd try anyways.

I'm currently living alone in my dad's house until he sells it, while him and my stepmom are living in Idaho.
My SO is coming to visit me two weeks from today (yay!) for the holidays. My dad just informed me that he is coming to visit for Xmas as well. I'll be happy to see him and spend time together as a family, except for one issue..

Whenever my SO and I have stayed at my dad's place, he hasn't allowed us to sleep in the same room. My dad isn't religious at all, but he was pretty strict on my sister and I when we were growing up. I've always obeyed and respected his rules, but I'm getting tired of this. I am 24, and my SO is 31. I'm more than old enough to share a room with my SO, and it's embarrassing and frustrating that we have to sleep apart at night. We only see each other twice a year, so I want to spend as much time together as possible. I would be more understanding if we were underage teenagers or from religious families, but neither of us are. I have a good relationship with my dad and I know he likes my SO, so I'm not sure why he's being so stubborn about this.

I've tried reasoning with my dad in the past, but he always says, "My house, my rules." Which is funny, considering he's told me before that it's our house, but now it's just his, I guess
I respect and appreciate the fact that my dad is letting my SO stay in the house with me, but I wish we could at least discuss the issue without him shutting me down.

Obviously none of you know my dad, but I'm sure many of you have experience getting through to men who don't express their emotions very often
Does anyone have any advice on how I can get through to him?
Thanks