Original Commentary
He should've suggested it *before* they went bed shopping

Modern Commentary
He might have actually meant bunk beds. I'm not sure he had a proper plan; we know that he didn't mean sleeping in the same bed, at least not at this point in their relationship.
He might not know how much free space is in her bedroom. She doesn't have much stuff and they could maybe fit two small beds.
What amazes me is that Kimberly does not at any point suggest that Brisbane move out. This is her apartment. He just showed up one day and moved in. But she's not going to give up the privacy of having her own bedroom- Terrence