Spencer has had a girlfriend all season - a girlfriend Spencer style. They almost met in person, but the meeting was left hanging when Spencer was concerned that his girlfriend Maeve's stalker was in on the meet. He thinks he was wrong at the end of that episode, but it turns out that, indirectly at least, he was right.
In 8.12, Maeve is in fact kidnapped. To rescue her, Spencer has to tell the BAU team all about his mostly virtual romance - no easy job for Spencer, who keeps his personal feelings and life pretty close to his vest. Turns out, after some twists and turns, that the kidnapper is a former student of Maeve's - a student with a grievance, brilliant and beautiful. Diane of course gets the upper-hand on the team for a while, and then-
What makes this episode so good is the unexpected tragic ending. Spencer risks his life to save Maeve, and we know he's not going to die. Diane takes her own life with a bullet in the head, and that's sad but not surprising. But the buller goes through Diane's head and into Maeve's, and presumably kills her.
The room and team are frozen in shock and sorrow. Spencer will for the most part recover, but he's encountered another breach in a life which just can't seem to bring him love. All of the team in one way or another have difficulties in their personal lives - comes with the territory - but Spencer's niche and burden continues to be one of the most interesting on television.
See also Criminal Minds 7.1: "The Is Calm and It's Doctor" ... Criminal Minds 7.3: Meets House and The Unit
And see also Criminal Minds in Sixth Season Premiere ... Criminal Minds 6.2: The Meaning of J. J. Leaving ... Criminal Minds 6.3: Proust, Twain, Travanti ... Tyra on Criminal Minds 6.13 ...Criminal Minds 6. 17: Prentiss Farewell Part I ... Criminal Minds 6.18: Farewell Emily ... Criminal Minds 6.19: Fight Club Redux Plus ... Criminal Minds 6.20: Emily's Ghost ... Criminal Minds 6.21: The Tweeting Killer ... Criminal Minds 6.22: Psycho and a Half ... Criminal Minds 6.23: The Good Lie ... Criminal Minds Season 6 Finale
And Criminal Minds 5.22 and the Dark Side of New New Media