There is a thread on here about this exact thing....it is very, very, very long with lots of back and forth answering. I'm not sure what the end result was but worth a look for you.
It's probably just a natural body odor- might be from the type of foods you or your family eats. If you have a pet that frequently "relieves" himself in your house, then that would explain it perfectly. Do take heed that I'm just throwing out knives in the dark here, If either of those explanations work for you, then I'm glad to have been of help.
People who smell like urine are often eating too much protein and not enough carbs and vegetables. It's a metabolic thing, and urea is formed in the bloodstream and sweated out in the skin.