Hi I've had sole custody for the past 6 years with ex having visits twice in 6 years he know wants custody he lives in Florida I live in New York he's paid no childsupport in six years and just got out of prison 9 months ago for crack cocaine he's been unstable for past 6 years and know has a live in girlfriend and claims he's more stable than me I've never been in trouble with law and I've been with same job for 6 years I've had 2 relationships over the past 6 years he's been in jail so many times for drugs can he get custody that easy

Let him try with that track record of no child support, not having more contact with your kid, etc... and you having had sole custody and taking care of your kid all this time what Judge would want to disrupt that for him?
My guess is that right of the bat the Judge would see straight through that as him looking for a way to get out of future child support and even going after you to pay child support to him.
That is most likely what he is thinking!