Sounds like several factors are at play here -- I don't think you're a psychopath because you wrote that you feel bad and expressed remorse. If you were truly a sociopath or psychopath, you would have no qualms about cheating on any woman and would get a sadistic pleasure of knowing you fool the woman you cheat on.

One reason could be that you have a co-occuring issue; you may like to engage in sex to numb yourself of another on-going issue you have which could be related to depression, alcoholism, drug addiction, porn addiction, something else that you compulsively engage in to avoid feeling pain.

Another reason is that you could just be emotionally immature and insecure about yourself, and for some reason, cheating makes you feel more mature and secure with yourself.

Another reason could be that you don't have a lot of friends (I don't know your gender) so the lack of social support and a social network means you seek out sex as a way to fill that void in your life?

You could just be impulsive and have unrealistic expectations for the role you want your sexual partners to fill in your life.

You could be angry and sad about your life in general, and the sex website and cheating is a way to feel better about yourself?

There's a million and one reasons why you did all of that cheating. Have you ever done counseling before? Maybe explore the reasons why with a therapist. But I don't think you sound like a crazy person. I think you sound like a lost person who is sad and wants answers.