Ben Affleck is "staying longer" in rehab because he's "committed to getting better".
The 'Justice League' actor checked himself into rehab for alcohol addiction one month ago on August 22 following an intervention from his ex-wife Jennifer Garner - with whom he has Violet, 12, Seraphina, nine, and Samuel, six - and sources have said he's "trying very hard" to battle his "demons", and will stay in the treatment facility for longer in order to make sure he tackles "the root of his addiction".
An insider said: "He is trying very hard to work on himself and get to the root of his addiction.
"He has a lot of demons but he wants to understand himself and have the results be different this time. He is committed to staying longer which is a very positive development. He is taking strides to better himself and is hopeful about the future. He is taking advantage of getting help and is happy with the way it's going."
Ben, 46, is also said to be committing to a longer stay in rehab in order to make sure he can continue to be "the best father" to his brood.
The source added to E! News: "He always wants to be the best father and this relapse put his family back in the public eye. He takes this all very seriously and will continue to."
The 'Batman vs. Superman: Dawn of Justice' actor previously entered rehab in 2001 and 2017, and after his stint last year he revealed in a lengthy Facebook post that he is determined to make a "positive recovery".
At the time, he said: "I want to live life to the fullest and be the best father I can be. I want my kids to know there is no shame in getting help when you need it, and to be a source of strength for anyone out there who needs help but is afraid to take the first step.
"I'm lucky to have the love of my family and friends, including my co-parent, Jen, who has supported me and cared for our kids as I've done the work I set out to do. This was the first of many steps being taken towards a positive recovery."