I can't trust anybody and i feel like every relationship i'm in the man is cheating on me and i still won't believe him sometimes how can i trust?

U need some help: You describe a not uncommon problem that can have one or more roots. It is a psychological problem that can be improved, once the source is determined. Your best bet is a psychiatrist, as you will need some exploratory therapy and possibly some medication. This is not likely to change on its own. It will take some courage. Go for it!

Worth Closer Look: Given importance of being able 2 trust in life -how it's the foundation of close relationships- u might consider seeking professional help exploring the basis of ur difficulties. Ur early experiences might provide some insight as might a careful assessment of ur beliefs about ur partners cheating on u; ur thought patterns, in general; etc. The cheating thoughts could be ocd obsessions, 4 example.

Trust: First and foremost you need to be able to trust yourself to read people accurately, some people can be trusted and some cannot. The key question is how do you know the difference. Group psychotherapy is an excellent opportunity to learn to read people accurately so you can protect yourself from people with poor character and identify those who have excellent character. Best.