Exiled Loki, he can't return to Asgard ever.
I'm trying to find a specific fic it has the pairing Tony/Loki, where loki is banished or exiled to earth and can't return to Asgard or he will be executed. Loki misses looking at the stars in Asgard, etc .I slightly remember one scene where Loki is on the rooftop of stark tower and accidentally projects the image of the void on the New York skyline(he ends up panicking and tony comforts him). As well as another scene where Frigga explains that she had a vision that Tony would help Loki, which was why they exiled him.... Sorry if this is too vague. Any help finding this would be appreciated ^_^
I'm pretty sure the fic was on ao3 or fanfiction.net