Question: how to stop thinking about someone who left you?
Answer: Stop Virtual Stalking. The last thing you need when you're figuring out how to stop thinking about someone is constant notifications about them. ... 
Toss Nostalgic Memorabilia. ... 
No Contact Rule. ... 
Move Your Body. ... 
Transport your Mind. ... 
Forgive To Forget. ... 
Respect Yourself. ... 
Let Yourself Feel The Pain.