You are pointing the finger at Husband as the only liable person. Often people will know, or suspect a conflict. Then reserve it, asking on Spouse's behalf. If the answers set your spine to tingle, you probably have a legal conflict of interest. Ask a professional.
Most conflicts are waivable if both parties are fully informed and consent, in writing.
Tax professionals are duty bound by their ethical rules and by IRS regulation to avoid conflicts, and to point them out to you when they arise or are likely to arise. Just be careful. If in doubt, ask. A little preventive maintenance at the start will avoid headaches later. Any references to products or services do not constitute or imply an endorsement or recommendation.