bro discuss with your wife nicely.
tell her you all got nice family with a son.

then ultimately, ask her nicely:

do you want to stay with our family, or leave to go with the boy?

give her some time to think, but not too long.

if i were you, i'd take the son and go live elsewhere. and maybe find a new loving,caring mother for your son.

and above all, pray hard to God and ask Him to show you the ultimate solution to your current problem.

good luck!