Wouldn't buy that explanation. If you have control over the decision to go on this trip, there is a good chance it would be deemed as taxable by the IRS. The portion for your spouse almost certainly is.

Note that even stricter rules regarding deductibility and documentation apply if the trip is outside the U.S., its territories, and certain Carribbean islands.

But I am not a CPA or tax lawyer either and you need to consult one!