As a writer:
The writing style of this story was very different from the others we have read so far. The skipping back and forth between present, past, and a hypothetical future created a disorienting and confusing impression that reflected the way the narrator was feeling. In the end, the reader is left wondering what is real and what is imagined. I was also interested in Machado’s choice to name the narrator’s ex “Bad.” From the very beginning it created the expectation that things in their relationship were going to go awry.
As a reader:
I am relatively sure that, near the end, the narrator had entered somebody else’s house under the delusion that it was the home from her fantasies (and that those fantasies had been real), and falsely identified the children as her own. This also calls into question whether the baby, Mara, exists at all in a literal sense. It seems obvious in retrospect that the baby may not be literal, since two women cannot conceive in the first place. I think Mara may be a representation of the trauma that Bad left the narrator with after their relationship ended; something that the narrator has to learn to live with and take care of. This also fits in with the narrator’s ex being a woman, since abuse in lesbian relationships can be underrepresented / not taken as seriously as abuse of women by men. The narrator automatically assumed that because her ex was a woman, they couldn’t make a baby, and she automatically assumed that because her ex was a woman, she couldn’t be an abuser.
I had not really thought about the idea that the narrator could have entered someone else’s house and falsely identified the children as her own. I did think that Mara never really existed, however, if your suggestion is true, it would be more painful to realize that someone else is living the dream you wished to have.