Think you carry both to show immigration. Not sure if passport office gives you anything else to show. Think you then transfer your extension to new passport. Wait for admin.
I'm really sad to hear your relationship was so dreadful. But a child, no matter what age, has to live with the pain of parents that are desperately unhappy and "hate" each other. I hope you can be there for your son, they are always our "babies" no matter how old.