should we sleep in same room?? Help!!

To make a long story short... I’m going to be 20 yrs old in 2 months , so is my boyfriend. We have been dating 2 years, are very serious. I sleep at his house all the time (my parents know), I’ve been alone on vacation with him several times, I went with him on his family vacation, and he went with us on ours (we shared a bed there!!) His job is 5 mins from my house and 30 from his, and he has crazy black friday hours and had to work tonight until 1 and tomorrow morning at 8. So he is sleeping at my house. My stepdad is insisting that we stay in seperate rooms, he is so stubborn and traditional. It makes zero sense!! Should I try to sneak it and lock the guest bedroom and my bedroom from the outside so he thinks that I’m in one of them if he checks? The guest bedroom is freezing and dusty, and I also haven’t seen my boyfriend in a few days and I want to spend some time together even if we are sleeping. Help!! What would you do!!