Liam Hemsworth is headed to the altar with actress Gabriella Brooks, but insiders say his ex-wife — “Wrecking Ball” singer Miley Cyrus — is seemingly trying to wreck his happiness by sniping he’s a lousy lover, a cad and the marriage is doomed. Sources say the 32-year-old “Heart of Glass” songbird hates her ex’s guts and hasn’t gotten over him — six years after they filed for divorce.

 <span class="wp-caption-text">SteveSands/NewYorkNewswire/MEGA</span>

SteveSands/NewYorkNewswire/MEGA

“Even all these years later Miley is still hanging on to so much resentment,” says an insider. “Looking back, she feels like Liam treated her terribly. And she was a huge pop star, so she can only imagine the way he’s treating Gabriella, who’s got nowhere near Miley’s level of power.

“She says she feels sorry for her. As far as Miley’s concerned, there’s zero chance Liam has changed and he’s bound to be playing all the same head games as he always has.”

“She’s telling friends he was selfish and cold and always left her feeling never quite good enough. The more time passes, the more she resents him and feels like he wasted years of her life.”

“It infuriates her that people think he’s this down-to-earth guy who just couldn’t handle life in the fast lane when it was the other way around.”

 <span class="wp-caption-text">SDB/ZOJ/Sheri Determan/WENN</span>

SDB/ZOJ/Sheri Determan/WENN

The pair dated for eight years before tying the knot in 2018, only to split eight months later.

According to insiders, Liam ran for the hills as they kept clashing over their differing lifestyles, and Miley later admitted in an interview on The Howard Stern Show, there was “too much conflict” to make it work.

 <span class="wp-caption-text">Getty Images</span>

Getty Images

Sources say to Globe that the bad blood has lingered, even though Miley has moved on with her own boyfriend, musician Maxx Morando, whom she started dating in December 2021.

Last month Liam, 35, sparked widespread speculation he’s made things official with Gabriella, 29, who was flaunting a massive rock on her engagement finger — and that caused his jealous ex to hit the roof, per People.

“Miley doesn’t buy for a second that he can make a marriage work,” adds the source. “She’s telling anyone who’ll listen that it won’t last.”