Is my ex entitled to any of my 401k if I had married and no martial money has gone in?

If you had the 401k prior to getting married and no funds were invested in the 401k during the marriage, then it is very likely separate property. However, marital funds are generally any funds earned by either spouse during the marriage. So, if you were putting money that you earned at your job during the marriage into the 401k even though you and your spouse kept your finances separate it would be marital money. If your Wife has a 401k and deposited money in it during the marriage, then it is at least partly marital and you can make a claim for at least of the marital portion.