This isn't the first complicated coupling Carter has been a part of -- and he hints the reason things get so complicated is because he keeps ending up in love triangles.
"I'm always caught up in those. I was caught up with Hilary and Lindsay and I'm caught up with stuff now," he points out.
Though he says he doesn't talk to either of his famous exes now, Carter appeared hopeful of rekindling something with Duff back in 2014, when he made multiple declarations of love for the Lizzie McGuire star. Which she agreed, at the time, were "weird."
"I've put out stupid messages. Things about being in love with her, when I probably just had too much wine or something," Carter now tells us. But he's moved on. "I would prefer to leave her life in peace, and I have a new love that I'm focused on," he says. "Lee is my new love. I'm writing songs about her, not Hilary."