Aikman confirmed the separation in a statement published on DallasNews.com, where he said it was "a difficult decision" for them both and that they "remain deeply committed" to their children.
The couple were married in 2000 and have two daughters together. Rhonda also has a daughter from a previous marriage.
The Dallas County Clerk's office said the Aikmans have not officially filed for divorce yet. But, according to the paper, property records indicate Aikman's wife bought a home in a neighborhood near their Highland Park home last November.
So far, Aikman has issued no other statement on the matter.
NBCDFW's Shane Allen contributed to this report.