character development

I love movies like this where the characters stretch and develop, but come up against human limitations. Each of the three did that. Hester left the stultifying role of being married to a person who was suffocating her, for something more "natural". She pushed herself to the limits to adapt to that relationship, but discovered she couldn't make it, and in the end, resigned herself to that loss, opens the curtains onto the day, and goes on living, saying "let's see what the future brings."
Freddie, who, as Hester said, "stopped living" at the beginning of the war and turned into someone basically self-involved and self-protective, tried hard to expand into someone more loving and caring, but wasn't able to. He ended up realizing he would keep hurting Hester, and so flew off to try to regain the thing that made him feel most alive.
William's pain over losing Hester motivates him to "regret" his past patterns, and want to try to do better. He seems to have learned a new sensitivity and understanding, but still has to drive off alone for the present.
These stories were so believable.
There was so much painfully honest dialogue, and the actors put themselves into the roles completely and believably.