Welcome to FlyerTalk - AA!
Chances are your wife would also return home alone, as AA would cancel the remainder of your trip when you didn't check in at DFW (no BP read as you board.) You can TRY to present a compelling reason to AA, like falling down in the aisle clutching your chest, but I think the airline is very familiar with the various ways peole try to bypass more expensive fares, change fees, etc.
! But, here it is...
American Airlines Conditions of Carriage
is what you need to look at (and memorize by heart!
) Lots of unilateraly and fairly binding verbiage that applies when we buy a ticket - the idea being we consent when we buy. May as well read and know your rights and responsibilities, IMO.
For others' convenience, the crucial bit says:
TICKET VALIDITY - COMPLIANCE WITH TERMS AND CONDITIONS OF SALE
Tickets are valid for travel only when used in accordance with all terms and conditions of sale. Terms and conditions of sale include but are not limited to:
The passenger's itinerary, as stated on the ticket or in the passenger's reservation record,
Any requirement that the passenger stay over a specified date or length of time (for example, Saturday night or weekend) at the destination specified on the ticket.
Any special purpose or status (for example, age in the case of senior citizen or children's discounts, military status in the case of a military fare, official government business in the case of a government fare, or attendance at a qualified event in the case of a meeting or convention fare) that entitles the passenger to a special or reduced rate, or
Any other requirement associated with the passenger's fare level.
Unless a ticket is reissued by American or its authorized agent upon payment of applicable charges, or an authorized representative of American waives applicable restrictions in writing, a ticket is invalid:
If used for travel to a destination other than that specified on the ticket,
If the passenger fails to comply with applicable stay-over requirements,
If the passenger does not meet the purpose or status requirement associated with the fare category on the ticket, or
If American determines that the ticket has been purchased or used in a manner designed to circumvent applicable fare rules.
American specifically prohibits the practices commonly known as:
Back to Back Ticketing:
The combination of two or more roundtrip excursion fares end to end for the purpose of circumventing minimum stay requirements.
The usage of roundtrip excursion fare for one-way travel, and
Hidden City/Point Beyond Ticketing:
Purchase of a fare from a point before the passenger's actual origin or to a point beyond the passenger's actual destination.
Where a ticket is invalidated as the result of the passenger's non-compliance with any term or condition of sale, American has the right in its sole discretion to:
Cancel any remaining portion of the passenger's itinerary,
Confiscate unused flight coupons,
Refuse to board the passenger or check the passenger's luggage, or
Assess the passenger for the reasonable remaining value of the ticket, which shall be no less than the difference between the fare actually paid and the lowest fare applicable to the passenger's actual itinerary