Louisa could only nod as Brian took her hand and gently guided her to their room. She climbed into bed. But she didn’t fall asleep again. A coil of fear remained – an ache, a pain she couldn’t rid herself of – the question of whether she’d hallucinated purely because of sleep deprivation lay heavy in her exhausted mind.

She waited for Brian’s deep guttural snoring to start, then she crept out of bed.

Her online search yielded a long list of hits. Louisa’s anxiety at what had happened – her belief she’d suffocated Noah when he wasn’t even in her arms despite her eyes telling her otherwise – lessened slightly. It seemed hallucinations were one of the most common effects of lack of sleep. One article mentioned that the effects of sleep deprivation could mimic mental illness.

Louisa began to panic that having Noah, and the lack of sleep that came with him, might have triggered her old problem. Or was the article right – was she merely experiencing the effects of not sleeping? She didn’t want to think about it. Louisa closed Google and was about to log into Mumsnet, but then decided Facebook might take her mind off things more. Thinking about what Tiff had said about Sarah, and the fact Louisa had never responded to being tagged, she thought now was as good a time as any to catch up. She may even find evidence of something going on between Tiff and Brian. They were both aware she didn’t really use Facebook and therefore would be unlikely to spot anything untoward – they may have taken advantage of that.

After a few failed attempts at logging in, Louisa finally recalled her ‘easy-to-remember’ password that Tiff had set for her and the homepage popped up. She immediately searched Tiff’s and Brian’s profiles. There were a few ‘likes’ – and Brian had commented on Tiff’s last profile picture she uploaded – simply saying ‘lovely’ – but surely that was nothing to worry about. She scrolled through the last two weeks of status updates, new photos and every comment on Tiff’s account, checking to see if Brian had said anything inappropriate. Then she did the same on Brian’s. Even though she was analysing everything as if under a microscope, she couldn’t find anything that looked suspicious in terms of them having an affair.

She then clicked on to Sarah’s profile. At first glance, her life looked perfect. Every photo Sarah posted showed smiling faces; happy families – on outings, all sitting around the table having a family meal, the kids all behaving. The picture of perfection – then she did the dirty? Facebook is a lie, Louisa concluded. In fact, she would go as far as saying it was evil. The fakeness appalled her. It was why she kept off it, although, deep down she knew that wasn’t the only reason.