Last Message ~Sayounara Watashi no Aishita Hito~

"Last Message" is a romance simulation of sorts with an odd twist: you love the guy, the guy loves you, and you have to dump him. 'You' in this case is young professional woman born with a silver spoon in her mouth, three months away from marrying a rich, good-looking heir to a major fortune. The only snag in this convenient turn of events is a beloved boyfriend/colleague of one year, who loves you with his heart and soul. The object of the game is to "break up with the love of your life beautifully."

[from AllGame]