My wife and I have been married for 20 years. She has not worked, is nit employable and does not have any marketable skills. She is 52 years old and a foreign national with poor English speaking skills. She raised our son, as a stay at home mom. He is 18 now.

For the past 3.5 years she has refused any intimate contact, to include sex, holding hands, hugging, or any other form of close marital contact. She does sleep in the same bed (Kingsize), cooks meals, cleans the house etc.

I can't tolerate this any longer, and intend to file for divorce. On what grounds should I file? Also I assume there is a large risk of my being ordered to pay alimony. Given GA law in this regard, the amount would be up to the discretion of the judge.

Any advice or thoughts?

Thank you

Georgia does not require grounds, you merely file. Expect that she will get some alimony since she has not worked, And you need to stop saying she can not be employed, since that only hurts you. She may not try to be employed.
hire an attorney and file

Most states no longer require specific grounds. Georgia is one of them. However, there are grounds that can be used, especially if she contests the divorce. This site should prove helpful about both filing and alimony. Georgia Divorce Basics - What You Need To Know | DivorceNet.com

When was the last time she visited her country? Would she like to go? Give her a trip home. When she's there, ask her if she wants to stay. She may be depressed and homesick now that your son is grown.

Just a thought. You can still file the divorce papers.