Trace Adkins and His Estranged Wife 'Are United' As Parents

March 26, 2014 — -- Their marriage may be over, but Trace and Rhonda Adkins vow to always put their children first.

"Trace and Rhonda are united in ensuring that their children's interests come first," a spokesperson for the couple said. "They thank everyone for respecting their privacy as they work through this personal matter together."

The singer, 52, and his wife of more than 16 years have three daughters MacKenzie, Brianna, and Trinity. He also has two daughters with an ex-wife.

Read: Trace Adkins Enters Rehab After Cruise Ship Brawl

Rhonda Adkins filed for divorce from the country singer earlier this week in Tennessee, ABC News confirmed, and cited "irreconcilable differences." She is asking for custody of the three girls and for the singer to pay child support.

"This was not a decision that was made lightly," a source said, adding that there had been problems in the marriage for some time. "It's a sad time for everyone involved."

Adkins checked into rehab in January for alcohol abuse after an alleged brawl with an impersonator on the Norwegian Pearl. He left treatment in February to be with his father, Aaron, who recently died at 71. After his father's death, Adkins returned to treatment and completed it.

Adkins had been sober for the past 12 years after completing a previous stint in rehab in 2002.