A New Leaf, 1971... super little film from Matthau and May.
https://encrypted-tbn0.gstatic.com/i...T4nptrL3TRHJaj
The original story included a sub-plot in which Henry discovers from the household accounts that Henrietta is being blackmailed on dubious grounds by the lawyer, McPherson, and a third party; and Henry poisons both of them. This darkly casts Henry's eventual resignation to lead a conventional life with Henrietta as his "sentence". By eliminating the sub-plot, Paramount got rid of the excess (3 hour) running time, avoided the awkwardness of Henry getting away with murder, and transformed the same ending into a positive and rather sweet statement of love and personal redemption.

