I think Haesoo and Mincheol had a registration marriage when they were fresh outta high school or around then, then Mincheol incurs the debt (probably bc he started to slip into arrogance) and he suggests that they get divorced so the debt won't be her legal responsibility to pay back. That's when they start scrounging on their resources and finances and Mincheol starts to hate Haesoo or whatever. This is why he keeps telling Haesoo that they were just strangers on paper and stuff.
This is what I understood from what I remember, so I could be off too
no you’re exactly correct
What is this remarry they are talking about? They were divorced because of the debt? But why? Btw, the cliff hanger.... (╯°Д °)╯╧╧