Lucy and Loke
Loke and Lucy also known as LoLu were first took action in episode 2 in the anime and the third chapter of volume one of the manga. The first time they meet Loke flirts with Lucy till he finds out she's a Celestial wizard and runs away. Later on in both the manga and anime Loke saves Lucy from trouble and they hang out. Lucy eventually finds out Loke is a Celestial spirit and saves him, and in return Loke become her Spirit. After a while Loki confesses his love for Lucy several times in the manga and Anime while Happy they Cat says " oooo they're in looooove ."
Lucy and Gray
Gray and Lucy also known as GrayLu first took action in episode 2 of the anime and the third chapter of volume one of the manga. The first time they meet Gray ask Lucy if he can have her underwear and in response to that question Lucy hits Gray with a bat/chair. Later on they become part of the same team with Natsu and Erza. Gray's relationship with Lucy really didn't start to form till the chapter and episode " Lucy Heartfilia" of the manga and anime. Where Gray is nothing but concerned for Lucy's safety and her feelings. As both context move on you see Gray mildly flirting with Lucy and beating Natsu saving Lucy. He and Natsu both come many time uninvited to Lucy's apartment to tell her things or ask for food and money. Later on Lucy becomes love rivals with Juvia for Gray.
Lucy and Sting
Sting and Lucy havent had any moments so far in the anime but, many fans of this couple have formed as sting does call Lucy blondie even though they are both blonde. So to please all the stilu/sticy fans out there here you go.
Lucy and Natsu
Natsu and Lucy also known as NaLu first took action In episode 1 in the anime and the first chapter of the first volume of the manga. The first time they meet Natsu breaks a spell that was cast on Lucy thus returning the favor she buys lunch for him and Happy. Later Natsu finds out that Lucy wants to be a part of Fairy Tail and takes her to the Guild to become a member. Later on they become part of the same team and go on many adventures together. You can see as time progresses Natsu starts to care for Lucy and Lucy for Natsu. Though she does fight with him a lot she's always there to support him. Lucy and Natsu save each other from many different situations as the anime and manga go on.Their relationship really kicked off after their battle with Oracion Seis, seven years has past since the battle Lucy comes back to find out her father died, and Natsu tries to comfort her.
Natsu and Lisana
Natsu and Lisana fist took place in the chapter and episode " Natsu and Lisana " in the anime and the manga. They fist met as children when Natsu came to the guild for the first time. Later on they developed a friendship as they took care of a giant egg that they found in the forest. Lisana during this time and forward calls Natsu her husband herself his wife , playing house in their hideout many times. Then Happy was born and all three of them became a family beyond no other. Lisana one day makes Natsu promise when she dies her will make her grave and he agrees. Lisana a few years later goes on a S-Class mission with her siblings resulting in her " dying " which we later find out she was just transported to Ebloas a opposite world. Natsu keeps his promise and makes a grave in front of the hideout to remember her. When in Ebloas Natsu cries in the site if Lisana being there.
Erza and Natsu
Natsu and Erza first took action in the third episode of the anime and the third chapter of the first volume of the manga. When they first met they were children and Erza accepts Natsu into Fairy Tail. As time goes on you see that Erza watches out for Natsu and encourages him a lot in both the anime and the manga. Later on on the episode and chapter" The Tower of Heaven " Natsu saves Erza from being absorbed by the lacarmia. In the episode " home " it shows what it would be like if Erza died it show that while everyone is crying and is sad Natsu believes that Erza couldn't be dead.
Erza and Jellal
Jellal and Erza first met as children when Erza didn't have a last name and Jellal named her Erza Scarlet, Scarlet for the color of her hair. Later on as children Jellal gets controlled by an evil spirit and threatens Erza's life saying there is no such thing as freedom. Erza always had a crush on him till he turned evil but she still cared for him. Later on Erza sees Jellal after they left the tower of heaven. He lost all of his memory only remembering the name Erza. She helps him turn good and he goes to jail to make up his time for all the past things he did, but later when training for the grand magic games they meet again and almost kiss. Jellal lies and tells her that he is engaged, thinking he is not worthy of her, though Erza sees through this lie and just plays along.
Levy and Gajeel
Gajeel and Levy first took place in chapter and episode " S-Class wizard" of the anime and the manga. In this part of Fairy Tail Gajeel becomes Levy's partner in the S- Class wizard competition to protect her because she is weak. During the second test they are attacked by two members of Oracion Seis Gajeel saves Levy telling her not to leave his side and to go find the others for help. Levy runs as fast as she can, but before she goes she gives Gajeel some iron for strength. Later on in the anime you see he relationship between Levy and Gajeel grow.
Juvia and Gray
This couple has been here since the phantom lord arc of fairytail. Juvia after meeting Gray had been released of the curse that she had of it always raining everywhere she went. she soon after first sight fell in love with Gray and even goes so far as to do anything to please him. Juvia gets jealous very easily over Lucy for just being close to Gray calling her "love rival" and death staring at her. Even though it is clear that Juvia loves Gray, Gray has shown no sign of interest in return though he does get jealous when Lyon claims that he is in love with Juvia forming the first ever love triangle in fairytail.
Juvia and Lyon
After Fairy tail's seven year gap Lyon met Juvia and fell in love with her at first sight. Lyon later became Juvia's Stalker, as she is to Gray. Lyon pops up during the anime to mess up Gruvia moments. Though because Juvia now has another love interest this causes Gray to feel "protective" of her. Thus starting Fairy Tail's second love triangle.