Is your ex receiving the funds received and reported on a Form 1099-R from your retirement account?  If so, then the amount that they receive is being reported on their tax return as pension income.  You would not be able to claim those funds as Alimony Paid on your tax return.

I write her a check each month a they have yet to submit paperwork to have it direct deposited into her account.

See the answer below from SuperUser bwa....

I agree with Don but you indicated that this is money that you pay from your retirement pay.  If you receive a Form 1099-R for the entire amount and write checks to your ex-spouse, the payments you make may be deductible as alimony. An IRS summary of alimony requirements is in Tax Topic 452, which reads as follows:

"Amounts paid under divorce or separate maintenance decrees or written separation agreements entered into between you and your spouse or former spouse will be considered alimony for Federal tax purposes if:

1. You and your spouse or former spouse do not file a joint return with each other,
2. You pay in cash (including checks or money orders),
3. The decree of divorce or separate maintenance does not say that the payment is not alimony,
4. If legally separated under a decree of divorce or separate maintenance, you and your former spouse are not members of the same household when you make the payment,
5. You have no liability to make the payment (in cash or property) after the death of your spouse or former spouse; and
6. Your payment is not treated as child support.

You may deduct from income the amount of alimony or separate maintenance you paid, and you must include in income the amount of alimony or separate maintenance you received.

Noncash property settlements, whether in a lump sum or installments, do not qualify as alimony. Voluntary payments (i.e., payments not required by a divorce decree or separation instrument) do not qualify as alimony.

My ex and I are separated with a legal document,  I pay her child support, alimony, and the portion of my retirement she will receive once we are divorced. How do I separate the alimony from the retirement portion on my taxes?

When was the legal document of separation executed?  Did that happen this year (2019), or prior to this year?

I pay my former spouse monthly from my military retirement. The divorce order states we are each responsible for our own taxes. Can I send him a 1099-R for the taxes I paid on his share ? Or can I deduct the amount of taxes I paid from his share ?

Depends.  If your retirement was split up like from a QDRO then he should be getting his own 1099R from the military.  If you just pay him then you enter the full 1099R and you pay the tax on it.  You might be able to claim what you give him as Alimony.

My friend gets part of her ex husband's military retirement.  It was split up and she gets her own check directly from DFAS and gets her own 1099R.  You need to ask your lawyer and the military how to set that up.

Ok so I have to give my husband half of my military retirement.  They split it from the gross income.  SOOOO that means I pay taxes on all of it and get less than half my retirement because i am paying all the taxes.  Is this correct?  Would it make a difference if I did an allotment? 

Have the military issue the ex their portion directly then you will each get a 1099-R for your portions only to report on your return.