Particularly for Paul and Julia, that love seemed deep, complex. When a baby carriage roles by and Julia looks wistfully at it for just one moment, Paul puts his arm around her shoulder and pulls her to him and walks them both away. There are no words required to know what's wrong and what's needed. And this theme of attending closely to the other's reaction, and responding appropriately all without words appears consistently throughout the movie.
The scenes that gives us a glimpse of Paul's adoration and support of Julia throughout her cook book project and Julia's support of Paul throughout regular moves with Paul's career do a beautiful job of showing the depth of their commitment to each other over time.