claiminf alimony payment

I am a military retiree, whom has been ordered due to my divorce, to pay a portion of my retirement benefit to my ex-spouse.  The funds are taken out and paid directly to my ex-spouse from DFAS, therefore, I do not receive the funds, nor am I taxed on that portion of my retirement benefit.  However, I heard that I could claim the funds as a deduction on my taxes since it is paid as alimony, and my divorce was before 2018.  Therefore, I need your validation on whether this deduction is authorized.