Same Time, Next Year

Same Time, Next Year is a movie starring Alan Alda, Ellen Burstyn, and Ivan Bonar. A married man and a married woman end up sleeping with each other, and decide to meet at the same place every year on the anniversary of their one...
A man and woman meet by chance at a romantic inn over dinner and, although both are married to others, they find themselves in the same bed the next morning questioning how this could have happened. They agree to meet on the same weekend each year—in the same hotel room—and the years pass each has some personal crisis that the other helps them through, often without both of them understanding what is going on.