"Heh. I... have a place I sleep at. I wouldn't call it a home." Home somehow implied that he bothered to spruce the place up - or at least clean it once a week - and it was a place he was supposed to have an emotional attachment to.
But his place wasn't a home in that sense. It was just four walls with enough facilities to keep him going through the daily routine. The fridge was only good for beer and the bed was only good for lying on and staring at the ceiling for hours on end, especially on the days when he was too afraid to sleep. Afraid of what might happen while he was asleep, afraid of what would happen during his sleep, afraid of seeing things while in his sleep that would jolt him right out of bed and haunt him for the next week.
"I don't wish to impose." That and, he didn't know if she was better off spending more time with him or without him. And because he didn't know and didn't want to risk anything to find out, it was easier to keep things the way they were in case his presence had an averse effect on her.
"But I will come by again, at your convenience," he reassured her, his voice and smile warm.