I love seeing that my girlfriend cheated and then made all kinds of posts about it.
Why do you like seeing these things?
Because first, I'm so heartbroken and second, look how ugly and upset her face looks.
Even though you are suffering it is not good to seek the pain of others. It will not really help in the long run.
I'm hurt, and seeing her in pain is making me feel better.
It's best to heal the hurt that you feel so that you can move forward. By seeking out opportunities to see another person in pain you are only prolonging your own.