Uh Oh!! It's gonna get U-G-L-Y

So Marc Anthony and Jennifer Lopez broke up back in the summer, Jennifer has moved on with a backup dancing Boy-toy. They were on Vacation with Jennifers kids, and when Marc Anthony saw the photos of new boy toy bonding with his kids and he "Blew Up"

He's thinking about going back on his agreement that Jennifer gets primary custody of the kids because he knows that will hurt her the most.......

Brutal.

Apparently Jennifer is all "Im still Jenny from The Block" and I will mess your (&^$& up! She's not gonna back down.