A Manhattan lawyer has been suspended three years for the frightening 45-minute physical and emotional assault of an ex-girlfriend.

In a decision released yesterday, the state Appellate Division found the lengthy suspension for Michael Zulandt was appropriate given the “calculated pattern of cruelty” he showed during the 2007 attack on the unidentified woman, for which he served a six-month jail sentence.

The judges said Michael Zulandt had gone to his ex-girlfriend’s apartment on Oct. 4, 2007, and “repeatedly” threw her to the floor “and slapped her.’’