And another said it looked as if the band was too small for her fingers and that her partner hadn't made the effort to find out her ring size, even after nine years together.
Jen later told Yahoo Lifestyle that she was delighted with the simple band, and it was exactly what she would have chosen for herself.
"He knew exactly what type of ring I'd love," she said. "A delicate, hammered gold ring with a tiny pearl.
"I don't usually wear any jewelry, but when I do, it's simple and minimal."
However, she was subject to nasty remarks such as: "It must suck to wait 9 years for a ring that look like that."
Jen added that she was shocked that so many of the people leaving negative comments on her announcement were other women.
"I was shocked to see so many females wasting their time replying to each other to dampen our happy moment," she said.
She explained that she'd deleted many of the hateful comments, but had seen a meme created from their photo and shared on Instagram with the caption: "Ladies, would you accept the ring and say yes?"
Luckily the couple also received plenty of supportive comments, with fans pointing out how happy they looked and saying that love is what matters - not the size of the ring.