Yes, in many fanfictions, Damon and Elena do get back together. Fanfiction writers often explore their relationship further and give them a second chance at love, as many fans were disappointed when they didn't end up together in the original series.
Often, in fanfiction, there's a time - jump scenario. After a period of time apart, both Damon and Elena have grown and changed. Damon has become more self - less, perhaps having worked on his issues with his brother. Elena, on the other hand, has realized that her feelings for Damon were deeper than she thought. They then meet again by chance and start to rekindle their relationship. Another scenario could be that a magical or supernatural event forces them to work together. During this time, they remember all the good times they had and fall back in love.
Stefan could be really interesting. Since he has a long history with both Elena and Damon, his reactions to their marriage would be complex. He might be a bit jealous at first but then come to fully support them, adding an emotional depth to the story.
One possible plot could be that after many trials and tribulations in their relationship, Damon finally proposes to Elena in a very romantic way. Maybe he takes her to a place full of their memories, like the waterfall where they once had a deep conversation. And then they plan a big, but also very private wedding, only inviting their closest friends. The wedding could be a mix of modern and traditional elements, with Stefan giving a heartfelt speech at the reception.
In 'A Marriage Story', they do end up getting back together. Throughout the story, we see them go through a lot of ups and downs. There are intense arguments and bitter separations, but in the end, their deep - rooted connection and love for each other overcomes all the obstacles and they reunite.
It depends on how you interpret the story. Some might think they do, as there are hints of a possible reunion. But others could see it differently based on their own understanding of the characters' emotions and circumstances.
Caroline would probably be really happy. She's always been a big supporter of Stefan and Elena's relationship. She'd be the one planning get - togethers and trying to make sure they have time alone to reconnect.
I'm not sure as I haven't read the book. But from what I've heard about the general themes in such stories, often the couple doesn't get back together as it's about the breakdown and consequences of a marriage.