siriuslikesmoonysbutt:

So it’s an everybody lives AU. Harry is in his early-mid twenties? Ish. And he wants to propose to his love (whoever you ship him with, it doesn’t matter for this headcanon). And so he goes to Sirius to talk about proposal ideas, because he knows Sirius is great at big grand ideas. 

Except he starts the conversation with “I know you don’t believe in marriage, but” and Sirius just interrupts him. 

“Why do you think I don’t believe in marriage?” Sirius is shocked. Marriage is great, he thinks. 

“You and Moony aren’t married,” Harry says. 

“Yes??? We are???” Sirius says, completely bewildered. 

“No? When did you get married? Did you two go off and do it without telling anyone?” Harry asks, honestly he wouldn’t put it past his uncles. 

“No… crap. We’re not married.” 

So basically Sirius forgot that he and Remus weren’t actually married. So instead of Sirius helping Harry with his proposal, Harry helps Sirius propose to Remus.