"Jesse is only my ninth boyfriend. I don't hang out with anybody unless I am in love," Kat told PEOPLE at the opening of her Wonderland gallery in West Hollywood on Thursday.
Asked if she thinks the motorcycle mogul, who accompanied Von D to the gallery opening, is "The One" for her, she answered, "I believe he is, so yeah."
As for how and when she first knew her feelings for James were so strong, she said, "Was it when we were playing Scrabble? I don't remember. But it was something like that – when we both realized how nerdy we were."
And although James recently finalized his divorce from Sandra Bullock after he admitted to cheating on her, Von D says the drama of his personal life didn't cause her to hesitate.
"I stayed away from that as much as possible, and when we connected recently, it was such a positive thing," she says. "It was just like, 'Wow, I can't believe I haven't spent this much time with you the entire time I've known you.' Now I'm just embracing it and enjoying it."
James was a tad less verbose about the romance, but when asked if he's happy, he replied, "Yes."
So, what does he like best about Von D? "Everything," said James.