Spencer Reid lost Maeve.
In Season 8, Dr. Spencer Reid began a relationship with a woman named Maeve, whom he had never met in person because she lived in fear of a stalker. This star-crossed relationship came to an abrupt—and tragic—end when Maeve was kidnapped by a deranged ex-student of hers.
The team raced to help Spencer find her, but they didn’t make it in time. Despite all of their efforts, Maeve’s student committed a murder-suicide right in front of them.