Josh Duggar checked into a rehab facility yesterday in the wake of his confession he was using the Ashley Madison website to cheat on his wife.

The Duggar family says it's a "long-term treatment center" ... but does not say what kind of treatment he's getting. While Josh's parents, Jim Bob and Michelle, have rarely admonished him ... they're directly ripping him now, saying ... "His wrong choices have deeply hurt his precious wife and children and have negatively affected so many others. He has also brought great insult to the values and faith we hold dear."

They added Josh's wife, Anna, is also getting counseling for her "heart and future" -- and they're praying Josh comes to "complete repentance and sincere change."