03/07/2007 at 05:00 PM EST
Men in Trees
hunk James Tupper's off-screen romance with costar Anne Heche didn't start until they were both single, he tells PEOPLE.
"The line," he says, "was never crossed."
Instead, the actor – who earned the on-set nickname "McTreemy" because of his heartthrob status among viewers – says he and Heche "really trusted each other almost right from the beginning" and leaned on each other as their respective marriages were coming to an end.
Tupper, 41, separated from his writer wife, Kate, late last year ("We remain very good friends," he says). In January Heche, 37, announced her separation
from her husband of five years, Coley Laffoon, 33, with whom she has a 5-year-old son, Homer.
Though their relationship did not begin immediately, the spark between the actors was clear once they started working together. "Anne and I have wonderful onscreen chemistry," Tupper says. "I'm happy that people like to watch us. It's a beautiful thing."
Adds Tupper, "I adore her, and I'm hopeful for the future."
But does Tupper, who says he'd love to have children one day, see himself settling down with Heche? "I'm not ready to rush into marriage," he says, but "I've never met anyone like her. There's something really comforting when you can truly connect with someone and be understood. Isn't that what we all want?"
For more on Tupper, including his road to success, his take on being a sex symbol and his favorite ways to wind down (hint: they include an oven), pick up this week's
PEOPLE, on sale Friday.