More information is needed with respect to how those payments to your ex are characterized by your agreement. And the date of your divorce. Your attorney can best advise you. 

the divorce decree or separation agreement could specify it's part of maintenance/support which would make it not deductible or it could specify it's alimony. if the decree/agreement was executed after 2018 or executed before 2019 and modified after that date and the modification expressly provides that the TCJA applies to it, alimony is not deductible 

A division of property at the time of the divorce is not taxable or deductible.  But ongoing payments would probably be characterized as alimony or support, even if they were directed to be paid to an IRA rather than directly to the ex-spouse.  In that case, they fall under the alimony rules and the answer is "no" if the divorce was filed after Jan 1, 2019, and "maybe" if the divorce was filed before Dec 31, 2018.  But it will never be deductible in the IRA section, because it's not your IRA.  It is either deductible as alimony or not deductible at all.  

Any payments, you make, that are deductible by you, as alimony; are reportable as income, by her on her federal income tax return.   

@Hal_Al --

Beginning Jan. 1, 2019, alimony or separate maintenance payments are not deductible from the income of the payer spouse, or includable in the income of the receiving spouse, if made under a divorce or separation agreement executed after Dec. 31, 2018. 

https://www.irs.gov/forms-pubs/clarification-changes-to-deduction-for-certain-alimony-payments-effec...