The library also has a copy of Then Comes Marriage that can be checked out. If it is available, it will be shelved on the second floor in Row 26.
In Short Stories for Students, look for "Happy Endings" in volume 13.
In Short Story Criticism, look for "Happy Endings" (Atwood) in the Cumulative Title Index. You will be directed to volume 2, pages 15 and 19-20, to volume 46, page 98, and to volume 142, pages 189 and 207.