Can my ex retire and do nothing and have the child support lowered?

My ex retired from a stable military career at the age of 39 and recently moved to the same state that I reside. The first thing he did was take me to court and have the child support lowered. He is now paying $500.00 less and he is lying to the court about what he makes. I know when you retire from the military you get 50% of what you were making, somehow he is hiding some of the money. He was making over $6,000.00 a month and now he is reporting that he only gets 1927.00 monthly gross income. My first question. Is there anyway I can find out how he is hiding the money? Second question, How can the judge be ok with him just setting around not working?
The judge projected an income for me as if I were employed and used that in the figures for the new amount. How can she estimate income for me since I'm unemployed with 2 children at home and my husband is our only source of income and my ex just gets to do nothing. My husband is a school teacher and we are tying to survive on a teachers salary. This does not seem right to me. Thank you.