i want to file for divorce but i dont want to lose my coop aparment. i purchased it with my 401k money after my marriage and my wife didnt put a dime

You say you bought your co-op after your marriage, but you also say you want to file for divorce. If you haven't filed for divorce, you're still married, and your ex is entitled to half the value of anything you bought during the marriage, as it is marital property and must be split equally between the parties. If you'd left your 401K intact your ex would only be entitled to half the value of your contributions to it made during the marriage. But since you liquidated it and bought another asset, she gets half of the co-op, regardless of whether she contributed to its purchase or maintenance. You bought the co-op with marital assets, and assumedly she hasn't had the benefit of using it- but she will have the benefit of half it's value once the marital property is equitably distributed. You cheated her out of her share of additional  401K contributions she would have received had you continued to contribute to the 401K instead of liquidating it- so fair is fair. You may be able to argue that her share should be reduced by the value of any 401K contributions you made before the marriage, but it's not clear you'd win that argument.