The French movie that Kate and Arnold see in the cinema is The Dinner Game (1998), which was remade as Dinner for Schmucks (2010) starring Steve Carell, who plays Dr. Feld.
When Arnold is getting ready to head to the airport, he puts on a dark tie with small stars. When he sits on the airplane it is a totally different tie.
Early in the movie, when Kay gives the leaflet to Arnold at the breakfast table, camera angle 1 shows him folding the paper and placing it on the table. Then it cuts to camera angle 2, and Arnold is folding the paper again.
Kay: I hate golf. I do. I think it's boring. And watching it; that's even worse. It's like being married to ESPN or something. And when you eat ranch chips... your breath smells.
Kay: He is everything. But I'm... I'm really lonely. And to be with someone, when you're not really with him can... it's... I think I might be less lonely... alone.