Overthinking

I have a problem with thinking too much. Ive always wished what it would be like if I could just sit there and relax without thinking about anything.
one thing I keep thinking about is getting cheated on. Or getting mistreated. I guess I dont have trust in people anymore. I feel like I could never get to be with someone anymore because I know that they will cheat. I have also lost faith in humanity. There just seems to be a lot of hate and carelessness in this world. Its too much to bare. One prediction of my future is that I will grow old and live alone , after dating people and breaking up with them because of infidelity. I really HATE people that cheat.