Selena Gomez and Justin Bieber finally called it quits last year after dating on and off for years. And it seems one particular feud caused them to split for good.

Gomez, 22, and Bieber, 21, apparently tried to make their relationship work but the "Boyfriend" hit maker's various run-ins with the law and rumored flings kept them from being together for too long. And in a last ditch effort to "save their struggling relationship," the former couple reportedly went shopping for engagement rings December last year.

However, they didn't quite make it to the actual engagement part.

According to an eyewitness who spotted them at a Tiffany & Co. in Beverly Hills, Bieber made it clear that he didn't want to commit, according to Hollywood Life.

A source told Life & Style that when a bystander asked Bieber and Gomez if they were planning on tying the knot someday, "Selena said, 'I hope so!'"

However, according to the witness, Bieber was, "mouthing the word 'No!' and he motioned with his hand to his throat like a 'cut it out!' sign, while shaking his head," behind Gomez's back.

It's no surprise that the pair never did purchase engagement rings and broke up for good soon after.

Meanwhile, the "Heart Knows What It Wants" singer is happily moving on with new boyfriend Zedd. And while she didn't get her happy ending with Bieber, Gomez is reportedly already planning her future with the 25-year-old DJ.

"She thinks Zedd is marriage material and perfect dad material. They've talked about kids and both of them want a big family. Selena says wherever they go, babies and little kids always gravitate towards Zedd because he's so silly and fun to be around. Plus, she says he's super patient," a source told Hollywood Life in a previous report.