Your question has many facets. Arfe you concerned about protecting yourself if the IRS audts the return and finds unreported income? You may be eligible for innocent spouse protection in which case the IRS will assess all fines and penalties against your spouse.

If you are concerned about his not disclosing income to you then that is a different matter. If he is employed you can always obtain copies of his employment records which would include compensation and benefits.

You may consult with a financial person to help trace expendityures against income. Your attorney should advise you.