The backlash has now prompted Sean Hunter, an elementary school teacher and the actor who played the husband in the commercial, to defend himself today in a post for Psychology Today . The ad was well received when it debuted in November, Hunter wrote, "But a few days ago, that all changed."

In the commercial, a husband gifts his wife a Peloton for Christmas, then she documents her usage of the bike, which costs $2,245 with a monthly $39 membership fee to access classes. The woman in the ad remarks she didn't realize "how much this would change [her]." Some onlookers complained about what they saw as undertones of sexism and classism in the ad, sending it viral on social media.

"My 5 seconds of air time created an array of malicious feedback that is all associated with my face. My friend texted me today declaring that I'm 'a symbol of the patriarchy,'" he wrote. "As my face continues to be screen shot online, I wonder what repercussions will come back to me."

Hunter wrote in the letter that the feedback he's received on the commercial has not been constructive and that his role in the ad does not define him. He concluded his note with a series of questions and a nod to his co-star, who is featured much more prominently in the commercial and has not commented on it.

"As I continue to reflect on the commercial, I consider these thoughts: Why are people creating so many additional narratives to the story? Am I allowed to view the commercial positively after receiving such negative feedback? If recognized on the street, what will people's first opinions be of me?" he wrote. "The aftermath of the commercial has left me with more questions than answers, and this is only half the story. I reflect on what my co-actor must be dealing with, as she's the other 25 seconds of the story."

— CNBC's Megan Graham contributed to this report.