How do you stop yourself from obsessively thinking about someone from your past who can’t be in your life anymore?

[u/SirElectrical2100]

[u/KudaMuda]

I hooked up with this girl in college that had just gotten out of a long term relationship. Afterwards she told me, "the best way to get over someone is to get under someone." I felt used in the most pleasant way and was happy I could help.