I have no faith that a romantic relationship can be healthy and lasting because of past experiences
Why dont you have any faith in having a healthy relationship?
There have been many times when my friends have expressed dissatisfaction with me for stepping out of line.
Dont let your past relationships shape how your future ones will be. You can have a great positive relationship sooner than you even realize.  This being said, every relationship requires work, and dont mistake this work for a bad relationship.
It's possible that I've never had a healthy relationship.
That may be so, but that doesn't mean you won't have one in the future! Your trauma is valid, but it shouldn't define you as it can be detrimental to your new relationships. How about trying to join some volunteer efforts, it can be easy to form relationships there.