YOU SAID:
I saw that you moved on with someone new
INTO JAPANESE
私はあなたが新しい人と一緒に移動したのを見ました
BACK INTO ENGLISH
I saw you moved with a new person
INTO JAPANESE
あなたが新しい人と一緒に動いたのを見ました
BACK INTO ENGLISH
I saw you moved with a new person
You've done this before, haven't you.