Unfortunately, there is not a black and white answer. If the money was earned during the marriage, then no question that the 401k is community but the problem is that he may spend all of it. If he does, then a person (you) may have a waste claim. However, the more time that passes before filing a petition for dissolution the less likely you are to recover your community portion/one-half portion. There is also a risk that both spouses are obligated to pay one-half of the taxes and penalties associated with the withdrawal. The sooner the better for taking legal action. A motion for Equal Division of Liquid Assets at that time of the filing for divorce should help too.