"Despite this being the end of their marriage, they continue to support each other," the statement reads. "They have worked together for 35 years and will continue to do so. They have asked that you respect their privacy during this time."
Blackstock has been McEntire's manager throughout the multiplatinum artist's career, which has included two GRAMMY wins and one Golden Globe nomination. Blackstock's management company also represents daughter-in-law Kelly Clarkson and Blake Shelton, who is going through his own highly publicized split.
The two have one son together, Shelby Blackstock, a race car driver. Blackstock has three other children from a previous relationship, including son Brandon, who is married to Clarkson.
In February, McEntire spoke to ET about her step-granddaughter, River Rose, and her husband.
"She's a doll," McEntire gushed. "She's been in London with her mom and dad and her granddad because my husband manages myself and Kelly. They've been over doing press for Kelly's new album [Piece by Piece] and getting ready for that release, so they've been really busy ... He's loving every minute of it, but he sends me videos and pictures every day, so I've been kind of keeping up to speed."
McEntire remains a pillar of the country music industry with her latest album, Love Somebody, having been released in April.