"Everybody on set now gets to see what goes on behind closed doors," the actor, 40, tells Redbook in its August issue. "We leave nothing to the imagination!"
In a way, though, being engaged makes it less awkward. "Our love scenes actually work really well," Moyer says. "Since the crew knows we do have chemistry and are together in real life, I feel like it takes away from the nerve-racking tension that can occur when people have to watch two actors who are just getting to know each other engage in an intimate scene."
Moyer, who popped the question to Paquin, 27, last summer, says he knew she was "the one" after they filmed the True Blood pilot – and then had to spend time apart.
"We were the only two actors who didn't live in Los Angeles, so we ended up going to dinner almost every night [while filming the pilot]," he says. "When we finished filming, I went to London and she went to New York, and it felt so weird not to talk to her. So, we began Skyping and have been together ever since."
Asked what he's learned from Paquin, Moyer says the primary thing she's taught him is the value of honesty. "Even if you know that what you'll say will hurt a woman's feelings, I've learned that it's better to be truthful with her than it is to cover up," he says. "Ultimate honesty is what a relationship is really about."