If you're married, tax refunds are generally presumed to be the property of both spouses. However, if the divorce arrangement (either signed by the two of you or ordered by the court) indicates otherwise then that will control. So unfortunately, the answer is "it depends" on what's in force. If you're not divorced yet then you're as entitled to the funds as she is. If you've not already, you'll probably want to consult with a local divorce attorney on the matter.
Good luck and best regards.
Evan A. Nielsen is licensed to practice law in California. The information provided here is for educational purposes only and is not intended as legal advice for a particular matter. This response does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult an attorney.
Unless there is an agreement or a court order, there is no requirement thast you give your wife half of your tax return. On the other hand, this could be considered marital property and she might be entitled to a claim. If you have not yet filed for divorce, you should do so ASAP.
On another note, your wife did not have the authority to kick you out of your home or to take your car. If you so choose, you can return at any time, even if the locks have been changed and you need to call a locksmith to get back in. Unless there is an order for exclusive possession, you are as much entitled to reside there as your wife is. Beware, though, that some people have an inclination to file false police reports to get someone out of the house.