AHHH FAIRY TAIL WEDDINGS. AND POSSIBLY CHILDREN. First would probably be Nalu? These dorks would probably be about 24 when they get married. I'd say they got together (as a couple) at either the end of the manga/anime or directly after.
Chapter 1- Nalu Proposal!
Natsu didn't think about these things too often. When he was little, he thought he would marry Lisanna, like most of the guild. But time changes things, and Natsu wasn't expecting Lisanna to come back, even though she did eventually. He didn't think about marrying her or anyone anymore.
However, he suddenly started liking it whenever Lucy was around, or wanting to be around her when she wasn't. Happy teased him for this all the time, but Natsu just couldn't stay away. A while back he had this "weird but good" feeling around Lucy, but he didn't really talk about it.
Eventually he realized that it was because he was head over heels for a certain Celestial Mage, but he just didn't say anything to her directly. When he did make his move, however, he was shocked (but ecstatic) to see that she was the same way. When they got together it was a huge celebration for the guild, and they'd been a couple for quite a few years.
Now, of course, with Mira's help, he decided that it would be best to marry her. Wasn't like he was going to marry anyone else. He didn't know much about these things, but he knew he needed an engagement ring (again, Mira's tutoring). They costed a lot of money, so he needed to take a solo mission.
"Hang on Natsu I'm coming!" Lucy yelled as Natsu was leaving.
"Sorry Lucy solo mission! See you in a few days!"
"Aye sir! Sorry Lucy!"
Lucy stood there, confused. It wasn't S-Class Wizard trials again, was it? Mira gave her a knowing smile, and Lucy became even more confused. She was probably the only one in the guild who didn't know what was going on, even though Natsu had made it quite obvious.
Natsu came back from his job and bought a ring. It wasn't super big or shiny, just a simple engagement ring. But to Natsu and Happy, it was the most precious thing ever.
"If you marry Lucy and have kids can I be Uncle Happy?" Happy asked.
"Of course you can, little buddy! Do you think she'll say yes?"
"Duh! She loooooovves you!"
Now Natsu had to know what to do next.
"So, what happens now?" he asked Mira (who approved of the ring).
"You have to get a blessing from her parents, if you want to be traditional. Of course, that won't necessarily be needed..." Mira's voice trailed off, her blue eyes saddening. "And then you have to get down on one knee and ask."
"No I have an idea! Okay thanks Mira!" Natsu ran off. Mira chuckled to herself. Silly old Natsu... Lucy had found herself a keeper.
Natsu visited Lucy's father's grave. He didn't know where her mother's was, but he didn't want to ask Lucy. He felt kinda stupid for coming out, but Mira said he needed parental approval, and he figured he had to do what she said, especially when it came to these things. He sat down in front of the grave. Happy sat on his shoulder.
"Hey, um, Lucy's Dad. I'm, Natsu. You probably don't know who I am, but um, I'm in Fairy Tail, Lucy's guild. I know you tried to take her away once, and I stopped you. Because Lucy belongs with us! In our guild. She always has, and everyone loves her!" Natsu said, smiling. "I love her too, and that's why I'm here."
"Aye!" Happy added.
"So, anyways, Lucy and I have been together for a while, and Mira told me that I had to ask permission before I marry her. But I'm not really the type of guy who asks for things, and you're dead, so it's kind of clear what I'm about to do." Natsu thought he heard someone walking behind him, but he ignored it. "I'm gonna marry your daughter. In fact, as soon as Mirajane tells me what to do, I'm gonna ask her and we're gonna get married!" he yelled. Then he said, softer this time: "Thought I'd let you know."
"Uh, N-Natsu?"
"Yeah Happy?"
"Turn around."
Natsu got up and turned around to find a teary-eyed Lucy. Natsu yelped and made a comical-anime face. Lucy smiled at him, which made Natsu calm down a little.
"Is there something that you wanted to ask me?" she asked.
"Yeah!" Natsu exclaimed, taking out the ring. Lucy's eyes shimmered.
"Happy what did Mira tell us to do next!?" Natsu muttered to Happy.
"Um, I forgot! I think you were supposed to go down on your knee!" Happy whispered back. Lucy laughed as Natsu clumsily sank to his knee, opening the box.
"Hey Lucy... Will you marry me?"
"Of course I will!" Lucy exclaimed, running into his arms and knocking Natsu to the floor.
"They're in loooooveeee~!" Happy sang. The three of them ran back to the guild to share the news with everyone, laughing and smiling the whole way.