It's hotly debated whether sex addiction is a real thing. Either way, your husband is a serial cheater, and those have a very poor prognosis in terms of ever being faithful in the future.
You need individual counseling to deal with this traumatic situation as well as your unresolved childhood trauma. Your self-esteem is obviously low, because you've known he hasn't been faithful one way or another before and throughout your marriage, but have quietly accepted it until now. That isn't your fault, because child abuse usually leads to low self-esteem. However, your low self-esteem is still a major problem nonetheless. Your actions have shown him and are showing him that he can keep doing this, and that you're going to stay with him regardless, because you don't feel that you can live without him. He knows this implicitly and that's contributing to his behavior. This will contribute to him cheating on you again in the future.
That is NOT saying that the cheating is your fault. It is 100% his responsibility, and you must kick to the curb any therapist who claims his cheating is due to you not communicating or not meeting some other of his "needs". Unfortunately, many marriage counselors are awful and don't understand infidelity, and typically blame the victimized partner rather than putting full responsibility where it belongs, on the perpetrator. Do not ever allow your husband to talk to you in this way, either. It's a common cheater dodge for them to talk about their "unhappiness" or "dissatisfaction" after they're caught, to try to make you feel guilty and/or inadequate, to take the heat off themselves and get you to try to be the mythical perfect spouse & convince them never to cheat again. Trying to be so perfect that he won't cheat is called "pick-me dancing" and does not work.
Honestly, since he's a serial cheater who has cheated from the very beginning, I recommend leaving him. I know you won't do so, however. I was also with an abusive serial cheater & wouldn't leave due to my isolation and low self-esteem, so I understand where you're coming from. I am telling you that staying is a bad idea. He's going to keep cheating at different points in your marriage, and eventually might simply leave you, because with this level of infidelity from early on, and his claim of "sex addiction" which is his way of saying he can't or won't control himself, it's clear he isn't going to stop. It's unlikely he's really in love with you, to have been so involved with other women the whole time. I'm sorry to be blunt but imo it's best to be prepared for the worst that will likely happen.
Even if you can't leave him and decide to rugsweep this (it's very unlikely this guy is motivated for and capable of the hard work of true reconciliation), please start making some plans on what you'll do just in case it doesn't work out in the future. Start squirreling away money, consult with an attorney for free just to get info, build friendships outside of your marriage so that you won't feel so alone if your marriage ends. Stop leaning so much on him and work to become more independent. Use birth control to avoid bringing children into this mess. And get STD tested, too.
I'm sorry you're going through this and I know how painful it is. You don't deserve it. You deserve better, but you're probably never going to get "better" from him.
[This message edited by morningglory at 4:04 AM, Tuesday, May 31st]