Councillor Pervez Choudhry, 52, was arrested on Monday and later released on bail.
Choudhry, who was originally elected as a Labour candidate for the Central Ward but later defected to the Tories, is due to appear at Maidenhead Magistrates' Court next Monday.
Peter Dale-Gough, the acting leader of the Conservative group on Slough Borough Council, said Choudhry had told him that he took part in a religious ceremony to his first wife but never went through with the civil ceremony and was therefore not married by law.
His second wife, a GP who was said to be about 10 years his junior, lives and works in Birmingham. He was said to have met her while using an online dating site and married her in Pakistan.
She was thought to have left Choudhury on learning that his previous marriage may not have legally ended.
Choudhry, of Slough, has vowed to clear his name, after agreeing to stand down as the Conservatives' leader.
He said: "I can't comment on the context of the case but I can say without any hesitation that I have done nothing illegal and I'm vigorously going to defend that.We have decided that I am going to step down and retake my responsibilities when I clear my name."
Last summer it was reported that Choudhry had been lucky to escape a suicide bomb attack while on a humanitarian mission in Pakistan.
He told the Local Berkshire newspaper he felt like he had "cheated death" after leaving his flat in Islamabad shortly before a bomb was set off at a building 15 metres away.
He said at the time: "If I had been there a few hours more I hate to think what could have happened. I feel like I've cheated death and am so grateful to my Lord for every day I have."
A spokesman for Thames Valley Police said: "A 52-year-old man has been charged with one count of bigamy. He was charged on Monday.
"Pervez Choudhry of Tuns Lane, Slough, has been bailed to appear before Maidenhead Magistrates' Court on the ninth of August."
Slough Borough Council delined to comment, saying it was a "private matter".