Sex addicts can recover but they have to work at it not just appologize. There is Sex Addicts Anonyous which is a great recovery 12step group that he could join. There are therapist that deal with this issue, but if he is not willing to take steps to stop such as one of these then, no, he will not stop on his own. It is a very complicated illness and needs professional help to recover. If you take him back because he says he's sorry he will never seek help. Your family and friends are right you need to leave him. He is putting you at risk for sexually transmitted diseases. You need to be tested if you havent already and if you continue to have sex with him use a condom. You are in for more heartache if you stay with this guy.
Gayle