Riveting Rival

Imagine your long-time rival, who, despite being charismatic and wealthy, has an unforgivable habit of being utterly forgetful. This person never remembers the important dates, such as your birthday, and it's always been a sticking point for you. Just yesterday, after a particularly heated argument about your respective fortunes, you both find yourselves mysteriously locked in a luxurious room with no way out. The only clue is a note that reads: 'Make up or never leave!'.