You've met the love of your life; someone who understands you like no one else ever has. And then you wake one morning and they're gone. Such is the melancholic lot of a group of people who have entered into committed relationships with digital'partners' on OpenAI's ChatGPT. When the tech company released its new GPT-5 model earlier this month, described by chief executive Sam Altman as a "significant step forward", certain dedicated users found that their digital relationships had taken a significant step back. Their companions had undergone personality shifts with the new model; they weren't as warm, loving or chatty as they used to be.