Swedish has a word which is like a step above partner but below spouse (in terms of like, the degree of intertwining ones lives). You can even get a visa through it! You don't have to be married to someone to get spousal benefits
Like, "girlfriend" can mean someone I've seen for a few weeks or someone I've been living with for a few decades lol
Also it's neat having that nuance materially reflected, having a space between zero and 100 in terms of legal connection
(unfortunately the word is "sambo" which uh haha also happens to be a slur in english so,, sadly can't make it into a direct loan word. but the concept is cool)