Healing trust issues is an inside job. It's basically losing trust in yourself, your own discernment.
It's very important to start working on healthy boundaries AND sticking to them no matter what.
That way your self-confidence can grow, and trust in yourself. You can then trust your intuition which helps in discerning who or what is right for you, or not.

The one thing that doesn't help is a full system shut down, shifting in distrust etc.
Then you cannot sense and use intuition which is exactly what you need to tell you what's good or bad.
Your boundaries should do the work, and your intuition.