To my knowledge taxes are not taken out each month. You will treat it as income on the return you file and will owe taxes based on your tax bracket. To compensate and not end up owing a large chunk of money at the end of the year, you may want to make quarterly payments yourself.
I am meeting with a financial advisor next Thursday for this very reason. Want to make sure I have enough money put into savings to plan ahead for tax time. I get child support and alimony. I know that the child support is not taxable, but the alimony is 100% taxable. So, I need to look into my options. As far as I am aware, I can have more of my actual paycheck withheld, to leverage what I will owe in alimony, or make payments ahead of time, or save up money for tax day...