Neville Longbottom
About two years after Rowena was born, Harry was forced to leave on an extended Auror mission. Hermione, meanwhile, was tasked by the Department of Magical Law Enforcement to investigate illicit activity in populated wizarding villages. She had to travel extensively for this task, which left her no choice but to place Rowena in the care of her parents.
Her job eventually took her to Diagon Alley. She was given an extended board in the Leaky Cauldron. There she met an old friend: Neville Longbottom. He was working on scholarly research for Herbology…while waiting for the Professorship on the subject to be vacant at Hogwarts.
It soon became a daily routine for Hermione and Neville to see each other. He would be there working in the upstairs flat he and his wife, barmaid Hannah Abbott, shared above the pub whenever Hermione came home from her investigative duties.
One evening, Neville was working over a Fanged Geranium feverishly. He was testing out the theory that a tenth medicinal usage for the plant existed, and would be a windfall for him if he was successful. Ever the scholar, Hermione sat on the four-poster bed, watching him. Hannah was away on business for the weekend.
"Alright, Hermione, this is it," Neville called. He dropped a chemical mixture out of a beaker onto the leaves. The leaves fizzled and then turned white hot as a bubbly gas began to seep out of them. Neville expertly plucked one from the branch and applied it to a purposeful cut on his arm that he had made earlier. Almost instantly, the cut faded away to only a scar. He laughed triumphantly and Hermione squealed.
"Oh, Neville, I knew you could do it! I just knew it!" she cried it. So great was her joy that she threw her arms around him and kissed him on the mouth. After a moment, she pulled away, mortified at what she had just done. Neville looked surprised too, then broke into an almost maniacal grin.
"Bloody Merlin!" he cried, and pulled her back into his arms, returning her kiss feverishly. Hermione let out a tiny whimper as their lips met. Soon, they were making out. Neville's hands wandered down her back, her bum and then to her thighs. He expertly hoisted Hermione up into the air, and she draped her arms over his shoulders to steady herself. Neville threw them both down on the bed. They trashed and kissed as both grabbed at each other's clothes. "Mmmm….mmm…" Hermione moaned. She groped for her wand and then cast a Diffindo charm. Her spell was muffled by Neville's mouth on hers, but her wand obeyed. Rips could be heard as both their clothes tore apart and fell away. Hermione wrenched her lips momentarily free from Neville's to gasp, "Do you have any protection?"
"No," Neville replied huskily.
"Me neither." They went right back at it. Neville stroked Hermione's vagina and she instantly felt wetness cascade around middle. She groaned and spread her legs wider, but Neville had other ideas. He pulled her up into they both were in a kneeling position. He continued to kiss her as he then spun her around so her back was to him. He then stood up on the mattress and the next second, Hermione's legs were up in the air. The wheelbarrow position. She had heard of it, but never had tried it before. Hermione lay there in a slanted handstand as Neville thrust himself into the crack of her arse. It was painful at first, but then subsided. The assuredness of the technique never wavered, and Hermione found that being fucked this way turned her on. "Oh…ohhh….OHHHH! Yes, Neville, yes!" she shrilly shrieked. Finally, she felt Neville come inside her. Both belly flopped onto the bed beside each other, exhausted. They smiled and kissed, rolling over in each other's embrace.
The next morning, Hermione woke up beside Neville in his bed. As she watched him sleep, rational thought returned to her after she had abandoned it the previous night. She couldn't keep an affair going with Neville. She did love him, but she wanted to remain faithful to Harry, even if he was away until further notice and likely would not find out. Even if he didn't, Hannah would. Hermione could do illicit activity, but not anything that would get out eventually. She kissed Neville awake.
"Sweetheart, I'm sorry, but…I can't do this. We can't. It's wrong. If anyone were to find out, it would be the end for both of us and our careers. Neither of us can afford that, but especially not you with all the success that's going to come your way."
Neville understood. Within the next few days, Hermione had completed her DMLE activities and ended her stay at the Leaky Cauldron. She said goodbye to Neville in his room while Hannah was downstairs brewing, giving him a clandestine kiss as she left. Many months later, while caring for Rowena and with Harry now home, she would be happy to learn that Neville's discovery had been patented, he had published an academic paper on the subject and had been awarded the Herbology professorship at Hogwarts.