That's all true. I do still feel wounded even from the potential relationship I almost had that only lasted five days and ended relatively well all things considered though. Even if it's unlikely I feel like the mere possibility for betrayal or making myself vulnerable turning out badly is terrifying enough to deter me again.
I heard an interesting quote and I think there's a lot of truth in it. Our capacity to love is equal to our capacity to be vulnerable. Along those lines, we are all vulnerable, and courage comes from vulnerability. It is not courageous if there is no vulnerability.
But being vulnerable doesn't mean setting aside reason.
If one jumps into a relationship, caught up in so many feelings and giving trust that can only be earned over time, until it is mutually built over hundreds of interactions between two people rather than given blindly and/or promised blindly, then shit's gonna hurt when the relationship gets cut off or the person proves they are not actually trustworthy. It's important to guard one's heart, even though one wants to give it, until the other person proves they value your heart so much that they want to protect it, too. That can't happen in five days. If one doesn't have tools for evaluating and making assessments, then they only act on hope, and that opens space for getting hurt, being manipulated, etc.
I had a super sociopathic boyfriend in high school. I would say he has the dark triad traits. He had a huge impact on me. I kept going back off and on for brief periods until my early twenties. In my mid-forties, after having had many relationships, I got involved with a guy who love bombed me and then got manipulative, started devaluing me, and became increasingly low-level abusive, which over time would have become egregious.
I showed him my good heart but didn't let him reside there, and when he proved without doubt that the good in him would never take precedence over his desire for a doormat rather than a respected equal and mutual partner. It was not easy but honestly not very difficult to recover because I consciously maintained my sense of my self and my values the whole time. I didn't change that for him. When he tried his narcissistic hoover technique a few months after his hyperbolic discard of me, it was briefly irritating but had no major impact as it would have in the years before, when I would have invested my self in the other person and lost my strong connection with my self.
Giving someone a big space in one's heart gives them big power, and I never gave him that kind of power, only a little. Now that there is so much distance between us, it is easy not to hate him because I have zero vulnerability to him. He can talk shit about me, I'm no longer part of the same community. He can date who he wants, I have zero interest in dating him and won't see who he's with (and manipulating) anyway. I won't accidentally run into him anywhere because I no longer live in the same area. He stopped hoovering, but if contacted me again, I would completely ignore him, because even negative attention fuels his shit.
I hope, if you wish it, that you learn things from this recent experience that strengthen you and add to your wisdom rather than weaken you and add to your fear.