What is the overall meaning of How I Met My Husband?

The story might not possess some overall and profound
meaning.  It might simply be that the path in which one finds love could be
fundamentally different than what one originally envisions.  Edie sees this path in one
direction and then becomes surprised when it turns out to move into another.  She really
believes that Chris will be her husband, and as she waits for word from him, it turns
out that the mailman that is meant to deliver this word ends up becoming her husband. 
Love is something shown to be unpredictable.  At the same time, I think that there is
an  idea present that people have to make compromises and some level of sacrifices in
the domains of love and dreams.  Edie really believes that Chris is her intended.  Yet,
must make some level of amends and settlement with her husband being the mailman.  When
he tells the story of how she could not stand to be apart from him, Edie lets it slide
and recognizes that there is little point in correcting him.  The story ended up turning
out in a particular way and Edie relents to this.