Most couples have a deal breaker that will spell certain disaster for a relationship: Cheating. Snoring. Liking an enemy sports team. That sort of thing.

For Gwen Stefani though, Blake Shelton's unwillingness to go on roller coaster rides almost pushed the pop star over the edge.

Appearing on The Tonight Show Starring Jimmy Fallon on Wednesday evening (February 15), the This Is What the Truth Feels Like singer revealed that the first time she and her beau went to Disneyland, she was (jokingly, we think) concerned about her future with Shelton because he would not go on a roller coaster with her.

"He won’t do the rollercoasters," Stefani complained. "That was literally, like, that was almost a deal breaker for me! I was like, 'I don’t know...'"

As it turns out, it's not necessarily that Shelton is afraid of rides—it's just that the country crooner is too tall to fit comfortably on some of them.

"He doesn’t fit in anything," she explained. "We did go on the Matterhorn, he did. But he barely fit inside the little thing. His knees were up like this!"

However, roller coasters weren't the only challenge she and Shelton had to face at the Happiest Place on Earth.

"I know that for me I just go anywhere, and I know I’m gonna get hounded for pictures or whatever," she told Fallon. "I don’t mind, you know what I mean? For him, he’s just not used to that, like I said. He’s in the woods most of the time but, yeah, we went. It was crazy it was, like, a billion people there!"

Watch her interview, below:

Gwen Stefani's Style Evolution:

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