Dvrced 2020,Jnt Custody now, so my question is since we both have jnt custody do i just include the single parent $ was sent plus one child do i just equally divide ?

Even though the courts considers you to have 'joint custody', for tax purposes, only one person can be considered the 'custodial parent'.  

The Custodial Parent is the parent that the child spent the most nights with (even if only one more night than the other parent).

If you claim your child as the Custodial Parent on your tax return, you would enter the amounts you actually received (or were supposed to receive).  The non-custodial parent cannot also claim the stimulus on their return (nor can you split it).

Whomever claims the child as a dependent in 2020 will get the full stimulus they are entitled to.

Click this link for more info on Stimulus Payments for Divorced Parents.