catfished by a nymph and coping with it

Strange title of a topic I realize, but this is my ordeal..

About 20 years ago I met a girl online and after sharing all of our sexual desires "we" decided to meet up. I put the "we" in quotes because it was mainly me pushing for this meeting and she got reluctant at the very last moment. I was persistent and decided to push through for this meetup because online we looked like a perfect match.

Turns out the reason she was reluctant to meet is that she was lying about herself the whole time. Mainly on her appearance (shared pictures that weren't hers), obviously this was crazy upsetting to find out face-to-face. I was far away from home and couldn't easily go back right away and somehow flipped a switch in my mind telling me to just try it out for the time I booked to be at her place.
She still wanted to try out our sexual fantasies and we ended up having some of the craziest sex in my life in those moments, multiple times a day for a few weeks in a row. Partly because I was really upset with her lies, I didn't mind doing some of these things to her that I wouldn't ever do to someone I truly love, and she enjoyed every moment of it, kept pushing the boundaries. Obviously, this didn't last and we split up soon afterwards.

Now years later I still am "haunted" by these memories and I am tired of them. I just want to say goodbye to them, but the truth is that they keep entering my mind and they turn me on. A part of me really enjoyed the debauchery from those times but its been too long and I'm done with it at the same time.

Hello and welcome.

Can you elaborate on what part of it, exactly, you are 'done' with? I mean, does what happened disgust you? Or do the thoughts simply pester you so much? Or that you find yourself pining for that experience again and you can no longer have that kind of experience for one reason or another?

I'm ashamed whenever these thoughts come back to me. I'm in a happy relationship where we are very open about our desires.. for example it's perfectly fine if I watch porn if I want to. In lesser details I even talked about this experience from the past, mainly because we want to be open about our past experiences.
But when these thoughts come back it feels like I'm succumbing to pure lust and it feels completely misplaced. In a way I'm disgusted with myself, thinking I'm weak to allow these thoughts to continuously arouse me while being in a great relationship.

So you think back to this far more than you feel is healthy, then? Considering you're in a relationship.

I can sympathise, to an extent. Not back to a specific instance in my past, or a specific person, but I'm bisexual and in an LTR, so I'm a bit familiar with itches that are not in a position to be scratched. And have fits of dwelling on it. It's rough sometimes.