I'm sincerely curious about something and I would appreciate if y'all enlighten me more, there's this trend of if a guy propose to you, like once he holds a proposal party, both the guy and the lady have automatically become husband and wife. The lady starts addressing the guy as her “husband” and vice versa, should that be a thing?

There’re many relationships that doesn’t get to marriage after proposal… it shouldn’t be a thing, but they’re trying to enjoy the moment.
Let them enjoy.