Every man has their own Emily, Summer and April.
I've always thought there is something more about this movie. There are three girls in Hayes' life, which is very likely to be representing three girls a man could be with throughout his love life.
Let's start with Emily - Hayes' college sweetheart. The one that he has been loving since day one, and it's only natural that he would want (and have a plan) to get married to her. But "love" of the first days wouldn't really last, would it? They had a long time being in love but once it's over, it's over. Hayes had a family with Emily, and it was a beautiful one. What they had is unarguable precious and he will always be thankful for having had her, but at the same time divorcing her is also an ending to things that are not as perfect as he thought it would be. Emily, in short, is the girl a man always seek for when raising a family. What they have in between is perfect, yet isn't.
The second one is Summer. Just like her name, love is filled with passion, sun-kissed dreams, romantic songs (Summer did perform a Broadway "I have a crush on you" for Hayes, and that's a great detail representing their vibes). At this stage everything is beautiful, but something is still not for guaranteed. Though everything clicks, yet something (if not, many things) has to happen. Maya asked if Summer broke Hayes' heart, and we all know she did. This is the girl that appears in every men's lives like a chill summer breeze, and left him right after that with a broken heart. She is Hayes' dream girl, and potentially his soul mate. But Summer and Hayes, they are like crossing lines. They only had a chance to be together once and then separate forever. Even if Summer did not write that article, who would be able to guarantee that they would get married and build a family? Even after that, Summer did admit that she didn't need a man in her and her baby's lives. This indicates that Hayes could be relieved knowing he can keep Summer as a beautiful memory, not a regret for losing.
Lastly, we have April. She's a very down to earth kind of girl. She likes teasing, she drinks, she smokes, she is anything but Hayes' ideal girlfriend or a mommy material. She's more like a friend. Hayes did say that they were good friends, writing, sharing, and caring for each other. The only thing he didn't say or realized until it's too late, is that he likes her. He never knew his feelings for her, since she's always been there. Don't you see how familiar it is? Men always have that girl in their life. More or less, at some points, they would feel something for each other, and in this movie, it's always the wrong time. They are always with someone else, yet they never want to lose each other. April might not be the best soul-mate for Hayes. She doesn't wear glasses or have gorgeous long brown hair like Hayes' "dream girl". She's not even romantic or shares the same political view with him, but she's real. She's there for him. She doesn't go away like a summer breeze or stop loving him when the time is over. We never knew if they ever got married in the end, but the important thing is, with her he's happy.
In real life, if the guy is lucky, Emily, Summer and April is the same person.
As for us girl, we really are are Emily, Summer and April at different points in our lives. Or maybe, again, all at once.
(P/S: sorry for my bad English!)