Para complementar o tópico:
Expressões relacionadas a "cortar relações" com o termo "through":
1.I'm sorry, Barack, we're through.(Los Angeles Times)
Me desculpa, Barack, estamos de relações cortadas./Não somos mais amigos.
That's it! Simon and I are through.(Longman)
É isso!Simon e eu cortamos relações.
2.Expressões relacionadas a "cortar relações" com "break off":
It seems Megan had this friend, a girl who lived a few doors down. Through seventh grade, they had gone round and round: best friends one day, feuding the next, the way kids do. Finally, Megan broke off the friendship for good. She was done with the other girl. But the girl was not done with her.[Dallas News]
==>Finalmente, a Megan cortou relações para sempre.
Unfortunately, Phil and I got into it and we broke off our friendship, it was the worst two years of my life, I missed my friend so much .[www.terrascope.co.uk]
==>Nós cortamos relações.