Thanks for all of your responses. After some soul searching and talking to a lot of friends and family I decided to sign the divorce papers as is.
There are a lot of things I was worried about including my ex trying to take half of my business in our divorce which he didn't so I wanted to get the divorce out of the way to protect my assets mostly. After all this is how I afford to care for my children. I also made more money then he did in our marriage and because of how things were between us I was worried he may try and get me for alimony as well. We've been married for 7 years now in February.
I honestly don't think he will fight me for custody in the future but if he does I'll be prepared to fight him when and if that happens. He has a lot of strikes against him including not paying court ordered child support, abandoning his son for years, tax evasion, multiple drug arrests, etc. so there is no way a court would grant him that if he fought for it. He knows that by his own omission so I'll cross that bridge if I have to.
I on the other hand have never been in trouble with the law, dutifully pay my taxes and have been the sole caregiver and provider for our child. I'm financially stable, have a nice home and am generally a more fit parent than my ex.
Our son was also recently diagnosed with dyslexia and dysgraphia and I'm going through extensive training with his school now to be the one who works with him to overcome these obstacles. So in short I am the most committed parent here, I don't think my ex would want to have to deal with what I have to deal with on a daily basis.
Again thank you all for your advice and thoughts. They are greatly appreciated. Hopefully in a few weeks I'll be a single gal again and can FINALLY move forward with my life.