Birth of a Beauty - cheating ex; upgrades to: a handsome
chaebol
Oh My Venus - cheating ex; upgrades to: a handsome
chaebol
Marriage, Not Dating - either the ex cheated or just didn't wanna settle down idrm; upgrades to: a nicer man of same or higher status
Witch's Romance - things didn't work out with her first love or something like that idr; upgrades to: a younger cutie
Prosecutor Princess - upgrade from first one-sided love to: a richer man who's just as handsome (though there was nothing wrong with the first man)
Others:
The Gentlemen of Wolgyesu Tailor Shop - not first love or anything like that, but homegirl is guilted into a relationship with an obsessive & abusive man. Definitely upgrades to a better man