Actions first, feelings follow.
No contact. Slam the door shut. This isn't fantasy, this is playing with fire. Fantasy is whatever plays out in your imagination without entering the "real" world.
There is absolutely no reason to beat yourself up about any of this. You're asking great questions, you realize you want something different than this. Those are HUGE steps.
Pray. Immersion into prayer and meditation can transform simple actions by transforming that space inside of us. So, whatever other actions you take, first take action in prayer.
btw- the "slam the door shut" analogy one day became very vivid to me after prayer. I was learning how to shut toxic people out of my life. They often look nice, say beautiful things and psychologically mess me up because they actually are very toxic. HP leads me to doing things that are beyond my own capabilities. Then looking back later I see how beautifully life flowed together.