I'd personally take his word that he's a sex addict. I wouldn't even be happy if my hubby were chatting up other women about oral sex. It is the first step to actually meeting face-to-face, methinks.
However, I am not an expert on this topic. I stopped in and saw your post hadn't been responded to as yet.
I suggest you ask him about going to see a counselor together. If he won't go, then go yourself.
Okay, other people----respond here, too!