"He is very much into clean, healthy living and supports her sobriety," a source tells PEOPLE about Cody Simpson

Nine months into their romance, Miley Cyrus and Cody Simpson are going strong.

The "Malibu" singer, 27, recently revealed she's six months sober, and a source close to the star tells PEOPLE exclusively Simpson, 23, has been as supportive as possible.

"She is very happy to be dating Cody. He is very much into clean, healthy living and supports her sobriety," says the source. "They are a great couple."

Earlier this month, Cyrus told Variety she became "sober sober" following her vocal cord surgery last November.

While her decision was prompted because of her physical health, the entertainer says her lifestyle change also impacted her emotional well-being.

Miley Cyrus Instagram
Cody Simpson and Miley Cyrus
| Credit: Miley Cyrus Instagram

"It's really hard because especially being young, there's that stigma of 'You're no fun,'" she told the outlet. "It's like, 'Honey, you can call me a lot of things, but I know that I'm fun.' The thing that I love about it is waking up 100 percent, 100 percent of the time. I don't want to wake up feeling groggy. I want to wake up feeling ready."

According to the source, Cyrus has felt "amazing" after embracing a sober lifestyle.

"During her recovery from vocal cord surgery, she gained a whole other mindset. She realized that she loved being sober," says the source. "She felt more productive and more focused, and she is maturing."

Now, "she is thinking a lot about the future," adds the source. "She would love a family at some point and plans on staying sober."

For all the details on Miley Cyrus' decision to live a sober lifestyle, pick up the latest issue of PEOPLE, on newsstands Friday.