If a hasband spends his wife's $10,000 in cash without her knowlege, is it illegal?

Tim from GA has found $10,000 in cash in his wife's closet. Without his wife's knowledge or permission, he spent all of that money on 1st class airline tickets to Asia. Now he is afraid that if his wife learns about it, she will have him arrested for theft by taking. Can he be held criminally liable for taking this money?