An average playthrough of this game is 18-20 hours. Two solutions:
1. Let the game idle for the remaining time. You'll need to set your controller settings so they stay on, and hook up a charging cable so the game won't pause.
Make sure you're doing this inside the simulation.
2. Play the game twice, once as a man and once as a woman. This will get you the Switch Hitter trophy and is a lot less boring than just sitting there!