assuming you were divorced at the end of the year for which he is trying to claim you then
to be a Qualifying Relative -
The person either (a) must be related to you or (b) must live with you all year as a member of your household.
this rule is not met if a) you were divorced at year-end because you are no longer related to him
and
b) you did not live with him for the entire year.
you cannot stop him from claiming you. if he files before you do and claims you, you will not be able to e-file. You'll need to mail in your return. use a tracking method so you know the taxing authorities get it. Eventually, the IRS will get around to making inquiries to both of you as to your dependency status. If you are due a refund, this can delay it and no telling when the issue will be sorted out.
