Nina Dobrev and Shaun White's broken engagement wasn't brought on by infidelity, a source exclusively tells Us Weekly. "There was no cheating at all during the course of their five-and-a-half-year relationship," an insider close to the former couple says. The source adds that Dobrev, 36, and White, 39, were fully committed before their breakup. "They were very loyal to each other," the insider tells Us, noting, "Any online speculation that suggests otherwise is ridiculous.