"How I Met My Husband" generates suspense because it waylays the reader on the reader's quest to find out the answer to the title posed in the question. The reader expects that the narrator, Edie, will answer the question of how she met her husband in the first part of the story, but Edie spends most of the story speaking about her interaction with Chris Watters. Chris is clearly a character with a lot of complications, as he already has a girlfriend, seems ready to take flight in his plane to escape his responsibilities at any time, and appears willing to take advantage of Edie, who is only 15. It is not until the very end of the story, within the very last paragraph, that the reader realizes who Edie really marries--the mailman she meets while fruitlessly waiting for Chris to write to her. Most of the story explains how Edie's unfulfilled quest for Chris's attentions enabled her to meet her husband, and the riddle of how she finally got married is not resolved until the last paragraph. 

By presenting the story regarding a young girl's infatuation with an older man, including the conflict with the presence of his "fiancee," and giving the story its title, the reader is led to believe that Edie (our narrator) is somehow going to run off and marry Chris, the airplane pilot.

Edie is really too young to be involved with Chris, but Chris in no way discourages her.  When Chris finds out his fiancee, Alice, has arrived, he packs up quickly and only tells Edie that he's leaving.

When Alice finds out that Chris is gone and Edie knows why, she turns ugly and accuses the young girl of being a tramp.  It is only after things have gotten totally out of hand that Mrs. Peebles is able to ascertain from Edie that she has only been kissed by Chris.

However, Chris had promised to write to Edie, which he never does-- but over the countless days that she sits at the mailbox waiting, we are surprised to learn that meeting her husband is related to that waiting, but that it does not include Chris at all.  It is not until the very end that the reader's curiosity as to how she meets and marries her husband is satisfied.