Staci has claimed that her estranged husband called her 22 times in two days!, RadarOnline.com has learned.
And her devoted father, Randy Nelson, has blasted Evan in an exclusive interview with Radar.
Staci posted proof on Instagram that showed all her missed calls from Evan, and wrote, "Is 22 missed calls in 2 days to an estranged wife really the behavior of a happy person?"
Radar first revealed that country crooner Evan, 34, had left his wife for superstar singer Lambert, also 34.
A source told US Weekly that Evan tried contacting her husband, the front man for the Turnpike Troubadours, to inform him of her illness.
Evan posted a cryptic message on Instagram, giving an update on Staci's condition and how she was "ghosted" -- or cut from communication -- by him.
But today, Staci is providing proof that he's been trying to make contact.
And in an exclusive Radar interview, Staci's father Randy Nelson slammed Evan, saying, "I'm sure Staci's four brothers would stick up for her too if they ever see him again!"
Outraged Randy also told Radar about his estranged son-in-law, "I'm sure he won't be around us anymore. There's no reason for him to be. I live in Arkansas, they live in Northwest Oklahoma, and he lives in who knows where!"
Explosive divorce papers obtained exclusively by Radar showed that Staci filed for divorce from Evan on February 28, 2018 in District Court of Oklahoma County.
She alleged that a state of complete and irreconcilable incompatibility had arisen between the parties, "by virtue of Respondent's abandonment of Petitioner, which has completely destroyed the legitimate aims of the marriage and rendered its continuation impossible," the scorned wife's petition read.
In his response to the petition filed on March 28, 2018, Evan admitted that a "state of complete and irreconcilable incompatibility has arisen between the parties."
But the musician demanded that Staci provide "strict proof" of the allegation in the ongoing divorce case.
Evan's neo-folk band was the opening act for Lambert on her Livin' Like Hippies tour, beginning in January — one month before the sudden divorce filing.
Evan and Staci did not respond to Radar's calls for comment on the new matter of him allegedly calling her multiple times.
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at firstname.lastname@example.org, or call us at (866) ON-RADAR (667-2327) any time, day or night.