QUESTION: Is it known for sure if the Apostle Paul was ever married? If so, what happened to his wife?
Answer: It is assumed by some that the Apostle Paul was married based on our historical understanding that, in order to become a member of the Sanhedrin, a man must take a wife. But while Paul was a member of the Pharisees, (See Acts 23:6) it is nowhere stated that he had ever become a member of the Sanhedrin (which was made up of Pharisees and Sadducees).
One thing we do know is that Paul was certainly not married during his days of serving Christ. Had he been married, his exhortation to husbands and wives in 1 Cor. 7:3 would have been completely hypocritical, since he also wrote that he had been given a gift of celibacy. (See 1 Corinthians 7:1-7).
Since we can't prove Paul was ever married, the second part of your question must unfortunately go unanswered as well.