Paul was a Pharisee; a member of the ruling counsel.
If a Jewish fellow was NOT married, he was looked at, shall we say, a bit funny?
Some scholars think that he HAD been married, and something must have happened to his wife.
Since he had experienced both sides of the fence, he could give his opinion on things.
Still, this is no evidence that he was married. Only your assumption which is not backed by scripture or Tradition.
Paul was a "young man" when they stoned St. Stephen. There is no indication anywhere in scripture or oral tradition that he had a wife.
Probably he'd never been married.