@goldenhandle,
Unless you are using a prostitute (which is an option I suppose) generally having sex implies a relationship. Most people arent looking just for sex, they want an intimate personal realtionsip too.
There is nothing you have said that makes an intimate relationship impossible. People who are overweight and minorities have relationships all of the time. Schizophrenia is a little more difficult. Dficulty with relationships is a symptom. However people who are treating there mental illness are able to have meaningful relationships that include sexual intimacy.
I suggest therapy. If the goal is to get you to a point where you can have a successful relationship (that includes sex) talking to a therapist is a very effective way to do this.