I am not licensed in MI, however, a lawyer who has represented you should not disclose information which would be harmful to you. That is not necessarily against the law, but may be a breach of his ethical duty.
He violated his duty to hold secret that which you told him in confidence. It is not "illegal", but is unethical. You can complain to the State Bar.
I am an Attorney-at-Law, licensed to practice law only in the state of California. Unless we have both signed a formal retainer agreement, you are not my client, and my discussion of issues does not constitute legal advice. Opinions expressed herein are those of the author, and do not necessarily represent the opinions of those who hold other opinions.
The Michigan Rules of Professional Conduct (MRPC) should be reviewed, especially Rule 1.6 (you can access them on the Michigan State Bar website). I suspect the question will be whether your actions were illegal or fraudulent and whether you used the lawyers services to further same, for if you did, the MRPC allows disclosure. If not, it doesn't. This inquiry would tie into the Michigan and Federal laws re: privacy, eavesdropping, protected communications, etc.