I thought we agreed to be each other's angels. Where did this sentence come from?

I went downstairs to buy ice cream, and I met a couple of dog men and women quarreling ... The woman turned and left crying: "You go!" " "The man's hand is still in his hand! The man held the woman in his arms as soon as he tried, and then said something that made me twitch until now: "No! I thought we agreed to be each other's angels! ! ! "... God knows how much I want to stick this ice cream on their faces ... I thought we agreed to be each other's angels ... this is a fucking classic. ...