From all I have read so far, I have the legal right to submit a 1099-Misc to my ex-wife for spousal maintenance, I just don't know which box to report it on, Box 3 "OTHER INCOME, or Box7 "NONEMPLOYEE COMPENSATION? Thank you to all who reply.

A payment to or for a spouse under a divorce or separation instrument is alimony if the spouses do not file a joint return with each other and all the following requirements are met.
*The payment is in cash.
*The instrument does not designate the payment as not alimony.
*The spouses are not members of the same household at the time the payments are made. This requirement applies only if the spouses are legally separated under a decree of divorce or separate maintenance.
*There is no liability to make any payment (in cash or property) after the death of the recipient spouse.
*The payment is not treated as child support.

If you paid alimony, then you can deduct it on your tax return. I do not think that there is any requirement that you send 1099-misc to your ex. She must report this income even without any form.