Garner and Affleck split in June 2015 after 10 years of marriage.
The pair’s public outings since their separation led to series of reports that they may be planning on reconciling.
But the report says there’s no chance of that happening.
“No matter what happens, Ben and Jen are committed to raising their family as one unit and will continue to do so as it has worked for them. They are both committed to their family,” US Weekly quotes a source as saying.
“It hasn’t been working for ages. Ben truly wanted his idea of family life and the idea of family he had growing up in Boston, so he stayed in it longer than he wanted to because of the kids and the idea of family. But he couldn’t save it.
“They were going to divorce when Sam was born, but you know how it is — baby comes and solves the issues for a bit, but it’s just a Band-Aid.”
Garner and Affleck have three children together: Violet, 11, Seraphina, 8, and Samuel, 4.
The Live By Night star was rumoured to have cheated on Garner with Christine Ouzounian, their nanny. Affleck is reported to have moved out of the Pacific Palisades mansion, which they bought in 2009. Garner told Vanity Fair in February 2016 that Affleck was the love of her life.