Well, he's had several months to get used to the idea of her Abnegation house being here, even before spring came and they were allowed out of the temple. He'd planned on moving there even before she showed; he had moved in for a few weeks. He'd cleaned, de-winterized the house and just begun to settle in because it was so much like the good parts of home and Tris that it was easy to settle in then she'd shown up. He'd always intended on moving out, on telling her about the house and never expecting her to let him live there. It's just that he wasn't (still isn't) sure how to tell her that her house is here given when she's coming from.

Well he did sleep on the floor next to her bed when she was here before because he didn't like her room mates so no, it's not above him.

"Yes, you do." He exhales. "Your parents' house is here. It's been here for months and before the winter I wasn't living in it. I couldn't, but after winter...I meant to just clean it up, de-winterize it, but it's more home than the temple. I'll move out and let you have it. It's rightfully yours anyway."

Creepy or sweet that he's been sleeping in her room? His choices were her parents (he wouldn't ever be comfortable there) or Caleb's room. He'd chosen hers because it was a way to be closer to her.