<human>: Can you give me a shortened version of the text?

My relationship with my ex (3years, 21y) was slowly declining; i was talking with her about ending it. Our relationship was the same from the beginning, just sex and talk, we never build anything together. We were meeting every Friday for a few weeks, and i had sex with her, even when i dated my new girl. I never had any courage to tell my ex about her.
My new girlfriend (20y) knows about my ex, but was unhappy in the way, how i tried to end my relationship with her. So there was no other way, i told my girlfriend about my new girlfriend and it all ended. But afterwards, i wasn't sure, if all feelings to my ex are gone. So i meet her again (3 months after having a new girlfriend, 1 month after i told my ex about her) and had sex with her, to find out, when there is any attraction between us. And there wasn't anything. But my new girlfriend funded out, about my experiment. What shall I do, to help her forgive me?
<bot>: I had sex with my ex to find out, if i feel something still to her. My new girl found out.