If YOU've successfully reached the true ending of "YOU and ME and HER: A Love Story", YOU must uninstall the game following the next steps:

• Open your Steam client and navigate to the "Library" tab.
  
• Locate "YOU and ME and HER: A Love Story" in your game library.
  
• Right-click on the game title and select "Manage" from the drop-down menu.
  
• In the Manage menu, click on "Uninstall."
  
• Steam will prompt you to confirm the uninstallation. Click "Yes" to proceed.

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And remember to never install it again if YOU really care about the characters of the game.