Divorce Support Forums: can a decree be changed?

Let me start from the beginning:
My ex-husband and I were divorced in 2004. We had been married for 8 years, together for a total of about 10 1/2 years. During the marriage my ex treated me horribly with alot of mental and emotional abuse. After dealing with it for so long, resulting in severe depression and basically losing myself, the marriage ultimately ended when I ended up having an affair the last few months we were together. I know that's not right, and I should not have done it, but I'm wondering if what he did to me was right? Because of my depression and everything that was going on, he basically brainwashed me into what he wanted...as usual. At first, he tried to take sole custody of the kids (we have 3), telling me that I would be proven unfit because of my indiscretion. Then he finally changed his mind and we agreed on joint custody because the kids need us both. He did however have me agree that neither one of us should pay child support because of this. He also kept our home, cars, just about everything we had. I basically only got my personal belongings. Again, he would tell me it was all because of what I had done and that no judge would grant me anything. He also led me to believe that his lawyer would just handle everything and therefore I didn't need one. So, his lawyer drew up all the papers and there I was in court with no representation, and him getting everything. Looking back I can't believe how naive I was. Is there anything I can do about this now? I was told by someone that even though we have joint custody that I can still get child support because my income is so low. I've been struggling with everything since the divorce. Like I said, I got nothing. He had savings and other money from the company he worked for but I didn't even think to even try because of how brainwashed he had me. To this day he is still very manipulative and thinks he can run all over me. I was forced to leave my home and find somewhere else to live. We had a suburban at the time, which was the car I drove and he verbally told me that he would make payments on it until I could into something else. He got tired of waiting, because he made me give the suburban back to him, which he almost immediately turned around and sold to get himself a brand new truck. Again, I got nothing from that.
Can anything be done now to reverse all of this? Can some of the divorce decree be "redone"?
Thank you so much for your time and assistance. I hope to hear from you soon.