I don't get what the big deal is here.
Just make sure everything is super cool and very chill.
By which I mean, every time she turns around, be there smiling and ever-ready to ease what meaningless task might impose some small burden on her day-to-day being, even if it's something she's been doing on her own for years. Be there. But smile, always smile. Don't let her not see you smile.
Greet the guys she brings home warmly. Tell them, "It's so great to meet you." It might not be, but say it anyway. And you're smiling, you're smiling.
Now, it's time for dinner. "Let me pay." You owe it to her since she's letting you shack up, but don't let that on. "It's my treat," you say (are you still smiling?) in a voice that is both very cool and super chill.
But oh, now it's bedtime. Awkward, right? People just have to sleep. It's time. No more weird smiles. Linger. Linger too long. Uncomfortably. Be there, almost agitated, but not quite. Bubbling, but not over. Not chill, no, not any more. Snatch the throw blanket she offers you. Look around in a huff. I mean, where do you put it? What the fuck?
Act weird and cold. Distant. Like she owes you something, which she doesn't. Act slighted, which you aren't. Grumble to yourself occasionally. And most importantly, update the OP.
It will be over before you know it.