Ideally, your divorce decree should set out the exact time frame for him to pick up the items before they are considered "abandoned." If you decree is silent, then the answer is more difficult. What most Courts look at is what is reasonable under the circumstances, but, usually, you would need to give him some formal notice, with a reasonable time period for him to get the items, before you sell or otherwise dispose of them. Because different judges in different jurisdictions have different ideas about what is reasonable, I'd advise you to have a local family lawyer review your decree and advise you on the best way to handle your situation.
I wholeheartedly agree with the prior poster that you need to consult a local (to the San Antonio area) attorney.
It is possible that, even if you waited what is considered a "sufficient" amount of time before you disposed of his belongings, a judge might not agree (really up to the judge's own idea as to what is sufficient) and you could be held in contempt or be exposed to some other liability.
Best to check with a local attorney who knows the judges' predilections - and maybe even a better idea to ask the court for direction if the decree is silent. An ounce of prevention is always worth a pound of cure.