If you were still married when he passed and you filed a joint return then you cannot deduct alimony ... that is alimony rule #1.
For one person to deduct alimony the other person must report it as income on their return ... so if you filed a joint return with the person who is "paying" you the alimony then the deduction & income would zero each other out ... so no alimony deduction or income is allowed on the joint return for obvious reasons.
In this case the IRS is correct so pay up.
