Christina Aguilera & Ex-Husband -- Divorce Is a Beach

Christina Aguilera and her ex-husband Jordan Bratman have called a truce -- at least temporarily -- and got together for a beach playdate with their 5-year-old son this weekend.

It's pretty commendable that the Xtina and Jordan played nice -- considering they went through a pretty nasty divorce ... with Jordan initially refusing to move out of the family home and forcing Aguilera to move into a hotel.

But this weekend, it was all smiles in Venice Beach ... where J & C came together to escort little Max to a birthday party.