While the movie doesn't involve a hammer, the premise is similar:
* Married man has an affair: Dan Gallagher, a successful lawyer, has an affair with Alex Forrest, a woman he met at a work event.
* Mistress becomes obsessive: Alex becomes increasingly obsessed with Dan and refuses to let him go, escalating to dangerous and threatening behavior.
* Wife becomes suspicious: Dan's wife, Beth, becomes suspicious of his affair and eventually discovers the truth.
* Mistress's fate: The film culminates in a dramatic confrontation where Alex's actions lead to a tragic outcome.
While the details differ, the core elements of a married man, an affair, and a suspicious wife investigating the disappearance of his mistress are present in both your description and "Fatal Attraction."