When did you know he or she was THE ONE?

Another related question: During your dating period which is prior to your engagement, did you have some “crisis period” when you need to adjust yourself to match each other’s expectation? It is hard to imagine that every couple will be completely “made for each other” and never have a disagreement or an argument before engagement or marriage.

Also, suppose that you had an argument occasionally, did you have more arguments (in terms of the frequencies and the degree/“intensity” of the argument) 1) before engagement, 2) between engagement and marriage, 3) after the marriage but not married for a very long time yet, or, 4) decades into your marriage life?

For us, I think it is either 1) or 3) – hard to tell in which period we had more arguments.