Chloe and Arthur died every day; more specifically, every night the current version of Chloe was killed by hundreds of other versions of Chloe. The next version would come to the window and knock, and the current version would go outside to meet her fate. The same thing happened with Arthur and with Henrietta, their hen. Since each Chloe lived only a day at a time, she didn't bother to do anything beyond eating and sitting in a chair staring into space. She was relieved that she didn't have to make a decision about whether or not to divorce Arthur or give him children.
When the Sixth Doctor came to the bed and breakfast, he too became involved in the daily deaths. After several days, he finally decided not to go the window when his next self knocked. The cycle of deaths was ended. Chloe and Arthur resumed their normal lives, but now Chloe had to decide if she wanted to divorce Arthur. (PROSE: The Death of Me)