Zac Affleck Says He Regrets How He Treated Jen Amid Divorce, Sources Say No Bad Blood

Zac Affleck is taking responsibility for his past behavior toward estranged wife Jen Affleck ... acknowledging his mistakes as the two navigate their divorce and prepare to welcome their fourth child.

In a lengthy statement posted to his Instagram Stories Thursday, Zac addressed the public discussion surrounding his marriage, admitting his words and actions were unacceptable and hurt those closest to him.

He wrote ... "I have taken full responsibility for my behavior, and I deeply regret how my actions negatively affected Jen throughout our relationship."

Sources with direct knowledge tell TMZ ... behind the scenes, Zac and Jen have strong communication and are on very good terms. We're told there's no bad blood or animosity between them despite their marital struggles.

As TMZ first reported ... Zac didn't participate in filming the upcoming "Mormon Wives" OC spinoff. He confirmed that in his statement, adding he hasn't watched any episodes. Zac said filming took place during a difficult period in his relationship with Jen, stressing that regardless of how events are portrayed or edited onscreen, Jen remains the mom of his children.

He added that he's acknowledged his mistakes and apologized directly to Jen, while continuing to work toward being the best coparent possible. Zac also said he and Jen have private conversations daily and are constantly working to be on great terms.

With Jen preparing to welcome their fourth child, Zac said the last thing he wants is to unintentionally cause her additional stress.

He also acknowledged that his kids may one day see the public discussion surrounding their family, saying he wants them to know both parents love them more than anything.