Kirk and McCoy are married. They have been since the 2nd year at the academy. At the start of the five years mission, McCoy has problem with Spock and doesn't get along with him but Kirk is getting along with him very well and they become fast friends to the point that makes McCoy jealous. McCoy himself finds a great comfort and confidante in Scotty and they start to have feelings for each other. Things aren't great between McCoy and Kirk and after a fight McCoy cheats on him with Scotty and when Jim finds out, he is very angry at first but then wants to work on his marriage despite being madly in love with Spock. The ending should be happy because dammit this is fanfiction! No transferring from the ship or character death.
Bonus point: I want a very long story with great character development. I don't want any character bashing.
Extra bonus point: I want lots of original characters. All of them from the crew and their relations to the main characters.
Extra extra bonus point: I don't want a uptight, serious Spock. I want him fun and a tease. I want him to be adored and loved by all of the crew. And I want him to have a lot of friends. And I want him to have had a lot of romantic relationships before and between Nyota and Jim.