How not to practice law: have affair with married woman, then agree to represent her husband in divorce

I haven't added anything recently to our running list of examples on how not to practice law, so here is a recent case that caught my eye.

Suppose an attorney has an affair with a married woman. Then the husband of the woman hires the attorney to help him get a divorce from her. Can the attorney take the case? Should the lawyer inform the client of the affair before taking the case?

Those are the facts of a case mentioned in the Tennessee Board of Professional Responsibility website. It states (here) that a Memphis lawyer was suspended for one year for engaging in a conflict of interest "by failing to inform his client that he had an affair with the client's wife prior to representing him in a divorce proceeding against the wife."

Thanks for the Legal Profession Blog for the link.