The Forsyte Saga (1967)

The elder generation of Forsytes gather at Uncle Timothy's to exchange gossip about two of the younger members of the family: James's daughter Winifred is engaged to the charming but financially questionable Montague Dartie, while Jolyon's married son, Jo, commits adultery with the Austrian governess, Helene. Old Jo overhears the gossip at Winifred's wedding, while Helene has bittersweet news for Young Jo: they are going to have a child.