I agree with K. It most likely if proven what ran the cc debt up will be his debt but it all is in the hands of the judge. I would in mediation try to get him to agree to put it in his colunm. If he does not then it is totally up to the judge.
Good luck to us both for I have simular with a home equity line that my stbx keeps maxed so I can not use it. He spends the money on gf and house and her car etc.