Loki (I remember it as him as a Jotun, but he may have had white skin) living in Asgard with his only son (whose name may not have been Jormungander or Sleipnir or Fenrir - it may have been an original name). I think he worked at a tavern as like a waiter or something.
Thor is King or close enough and married to the Queen, Sif. They have a child, a little girl with golden hair.
Thor ends up meeting Loki and they have an affair and somehow Loki ends up in the palace and watching Sif’s daughter when there is an assassination attempt on her and Sif begrudgingly accepts that Thor’s affair with Loki happened and she can’t undo it.
I also remember that Loki (near the end of the fic maybe) gets money from Thor and makes a shop that I believe sells ice cream.
Disclaimer: For all I know, this could actually be three different fics, but I really remember the shop part the most.