I am sorry you are in such a lonely place 🙁
New relationships are HARD for this very reason, especially if you are a person whom has a hard time trusting people.
I do not really have any advice, only a theory on how I have dealt with relationships. I come from a history of being hurt time and time again. I have had trust issues – with MOST men in my life, including my father.
At some point, I just had to tell myself that those that have hurt me in my past are not the same person as those I meet along the way. And so, I believe that each new relationship needs to start with 100% trust. If or when that person breaks that trust, that is when it gets diminished or demolished, and one needs to either protect themselves and move forward, or work with that person to build it once more.
My SO is not perfect by any means, no one is. In the almost 3 years we have been together, there have been times where trust has been diminshed. However, not to the point where it was not fixable, or something we could not overcome. There have been times I have done the same to him! Our trust issues were not due to major factors, such as, cheating or betrayal, but rather little lies we told, or questioning if this relationship was right for one another, etc.
In the end, I never ever put a past relationship hurt into my current one, and for that I have been the happiest with him than anyone before! So, whereas my last long term relationship went, he had gone out with the boys, and never came home. I found out later – much later – it was bc he hooked up with a gal he met out. The first time my SO had a boys night, I ‘went with the flow’. Although a fleeting thought had passed thru my mind regarding my past (WHAT HAPPENS IF HE DOES NOT COME HOME?!), I remained calm – telling myself that I need to trust he will, and only worry about it if the outcome differs.
He came home, he told me about his night, he PROVED to me that not all men are cheating scumbags, and our trust remained 100% intact.
Maybe my theory is wrong, but it has worked for me. And although throwing ‘counseling’ out is not always the best option – for you, OP, I would seek it out. Only because you stated you have never trusted anyone 🙁 Good luck!