To let go when people chose to leave.
It took a lot this time, but I accepted sometimes people don't feel the same as I do. All because I feel like I miss someone, doesn't mean they do. I needed to accept I'm not gonna die of sadness because someone else can get past things I can't.
There are more people in this world to be stuck on someone, when there's people out there who will be interested in you and hang on your every word when they care. When I finally realized this, I started letting new people in.
Allow yourself to enjoy when people are around, but when they go stop trying to show them anything, its okay to let them leave and move your effort to other people.
After all the pain and suffering after they leave, it really is just a matter of time before the new prince/princess charming shows up. Fix your make up girls, it's just a break up.