Sorry for the giant text, and thank you for the ones who have the patience to read it.

TLDR.: Had a traumatic experience with NM that led me to go back into having an open relationship with my girlfriend. Now I'm afraid to try polyamory again and feel all the bad things I felt in the past.

T.W.: mention to meltdowns, anxiety and self harm

This is something that happened 5 months ago, but only now I'm being able to write about it without feeling completely anxious

I like the idea of being NM/polyamorous since 2020, have tried a few times and learned from my mistakes, wich takes me to my current relationship with my girlfriend (22mft)

We started going out in the beginning of 2022 and since that time I told her I didn't wanted a full closed relationship. We started with just an open relationship, until I developed affection for someone else in the middle of the year (ended up losing interest for that person before anything sexual or romantic happened). We started discussing about having romantic relationships with other people and, in a few months, she met a girl and they started dating.

I swore I would take this situation lightly, but I just couldn't. I was terrified of being abandoned every day and spiralled to a state of constant anxiety. I refused to leave her side (skipped several days of college), was an insecure and sad mess of a person. Started taking antidepressants and sleeping pills. I could se how tired she was of me, and how happy she felt when talking to her other partner, and felt something very close to physical pain. I had meltdowns were I would hit my head on the wall, punch and bite myself, to the point where my gf had to leave a party in order to physically restrain me.

The guilt was the worse. I hated to feel like the sad part of her life, hated being the one that suggested NM and was now suffering because of it, hated everything about my behavior.

She ended up breaking things up with her girlfriend (because the other girls morals didn't matched hers) and we spent some time focusing on us. She admitted to feel exhausted by my behavior at that time and that, if things had kept going on like that for a few more months, she would break up with me. This was in the end of November/star of December.

We were closed for a couple months and are opening the relationship again, but agreeing to be ourselves only "serious partners". I'm taking my meds, doing therapy, went back on testosterone (wich will increase my libido and gender euphoria) and I'm also focusing on my studies, myself and my beautiful relationship. I truly love absolutely everything about my girlfriend and want to have a future with her!

But I'm terrified of what will be of us. I don't believe in monogamy, and always saw an open relationship as a bridge for ENM. My gf says that the most important thing here is our relationship, so it's okay for her if I decide we'll be only sexually open or even fully closed. I don't think it is possible to flip a switch in your brain that will make you not fall in love with someone else just because you're dating.

I'm afraid of how it will be if she starts seeing someone else. Afraid of falling in love with someone and having to choose between living all that hell again or giving up one of the people I like.

Honestly, I don't want to go back to that! I don't want to live that hell again! It was one of the worst moments in my life. I still have nightmares about it and cry a little bit when I remember how I felt. But, at the same time, I feel like an hypocrite, coward and an idiot for giving up NM.

Any advice is appreciated, thanks!