Jan 13 (Reuters) - A former partner at a major Boston law firm has filed a lawsuit claiming that an affair between his wife and the firm's managing partner cost him his job.

Lawrence Cohen brought an action on Friday in Delaware Chancery Court against Edwards Wildman Palmer and its managing partner Walter Reed, alleging that an affair between Cohen's wife and Reed gave him no choice but to leave the firm in November. Cohen's wife Laurie Hall, is also a partner at Edwards Wildman.

A second plaintiff in the lawsuit is former Edwards Wildman partner Jay Rosenbaum, who claims he lost clients that were "inextricably linked" to Cohen and that he, too, had no choice but to resign. Rosenbaum and Cohen, both estate planning attorneys, are now partners at Nixon Peabody.

The lawsuit asserts that Reed's alleged affair with Hall, a partner in Edwards Wildman's estate planning practice, led to Cohen's loss of a leadership appointment and clients and to lower pay. He claims that the situation forced him to resign in November.

Cohen and Hall separated in September. It is unclear if they are divorced.

In a statement, a spokesman for Edwards Wildman said, "The firm has received a copy of the complaint and the claims will be contested in the course of the proceedings." Reed and Hall declined to comment on the lawsuit.

Cohen and Rosenbaum did not respond to messages seeking comment.

The l9-page complaint asserts that Reed and Hall began an affair in 2009. Cohen claims that because of the affair he was excluded from firm events, including two weekend leadership retreats. The complaint also alleges that Hall and Reed in 2010 began "to spend increasing time in the office alone and behind closed doors." The lawsuit further alleges that Reed and Hall announced their relationship to a meeting of firm partners in November and said that they were divorcing their spouses.

Cohen and Rosenbaum assert breach of fiduciary duty and constructive discharge. The lawsuit seeks a portion of the plaintiffs' 2011 gross billings and the full amounts of their capital accounts.

(Reporting by Leigh Jones)

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