If Neville Longbottom and Hannah Abbott were Muggles, they would be considered DINKs.
However, the wizarding world doesn’t quite have a word for a dual-career couple who have chosen to remain childfree, and so Neville and Hannah are anomalies, spending their days managing Herbology classrooms and Leaky Cauldrons, respectively, and ignoring the continuous hints that it might be time for the two of them to think about settling down and procreating.
They are, at least, spared the well-meant reminders from their respective parents. It is a reluctant blessing, given that Hannah lost her mother during her sixth year at Hogwarts and that both of Neville’s parents still live permanent lives at St. Mungo’s and will do so until Neville and Hannah make the choice to change that circumstance. As it stands, a good chunk of their combined salary goes into supporting the life support spells that keep Alice and Frank Longbottom alive. (Neville only realized as an adult how much this must have cost his grandmother.)
Neville was one of those awkward teenagers who never figured out who he was until he was able to make his own way in the world as an adult. Hannah had the stronger sense of self when they were younger, and it was she who proposed the courtship, proposed the proposal, and managed much of their early lives together. Now they stand on more of an equal footing.
Hannah still manages much of the finances and the day-to-day logistics of their lives, but Neville—whom their friends like best, secretly—manages their social calendar. They hold parties above the Leaky Cauldron, often. (Hannah watches as people flirt with her husband, whose attractiveness has improved significantly since his schoolboy years.)
Neville invites his students to special gatherings, in part because they interest him and in part because he knows he interests them. He and Hannah both, showing these teenagers that there are other paths in life besides becoming parents. It is possible to be an adult and still enjoy weekend lie-ins, long conversations into the night over Ogden’s Firewhiskey, strange Muggle music played on a refurbished turntable Neville bought off Arthur Weasley.
They drink a little too much, vacation as often as they can, read countless books, try to ignore the images of war and death that still occasionally turn up in dreams or at the bottom of a glass, and enjoy the lives they have earned as adults. Hannah takes courses to train as a healer. They visit Neville’s parents. They think how glad they are that they’ll never pass that burden along to their own children.
Yes, Neville sees Luna occasionally. Hogwarts students so very often marry their school sweethearts that Neville still gets teased about Luna, as if he had ruined everyone’s expectations by marrying Hannah instead. (Given that Hannah had gently guided the majority of their relationship, Neville also sometimes wonders what it would be like if he had followed his youthful impulses and pursued Luna when he had the chance.) Hannah and Luna are not friends, although they all meet for Sunday dinner every few months, Hannah and Neville with Luna and Rolf and their two children.
When they get back home Hannah and Neville are both relieved to remember that there are no surprise children waiting for them there, that they can simply climb the stairs to the apartment above the Leaky Cauldron, close the door, and go back to being themselves.