A source told PEOPLE this week that Garner, 46, is the most concerned about their three children — Samuel, 6, Seraphina, 9, and Violet, 12.
“Her number one concern is the kids,” the source says, noting that Garner, 46, has been hoping to finalize her divorce from Affleck soon, but “struggles” with questions like, “Is Ben healthy enough to have custody? Can she rely on him to co-parent?”
The move for Affleck, also 46, to enter a treatment facility came after Garner was photographed at his home on Wednesday. The Peppermint actress was seen leaving Affleck’s home upset and shaking. When she returned, Garner, Affleck and an unidentified woman who arrived at the actor’s home with her left in a car the actress was driving.
Garner stopped by a Jack in the Box fast-food restaurant before the trio drove to a treatment facility in Malibu.
Another source told PEOPLE that Affleck “knew he needed help and was vocal about it.”
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Affleck’s return to treatment comes after he was spotted out with 22-year-old Playboy model Shauna Sexton in recent days.
As for Garner, “what she ultimately cares about is his sobriety,” the source says. “Her concern right now is not who he is dating.”
The source adds, “In the past, Ben hasn’t been doing well when he is alone.”
The day after a fast-food date with Sexton on Monday, Affleck appeared to receive an alcohol delivery to his L.A. home. In the photos, he held a Pacifico beer-branded box containing what appeared to be Johnnie Walker Blue Label scotch whisky in a blue case and some other unidentifiable bottles.
Sexton told Playboy in an interview in May that her drink of choice is “whiskey all day.”
Affleck turned 46 on Aug. 15, and just before the big day, a close friend of his told PEOPLE that “Ben is doing well. He is in a good place mentally and has worked really hard to get there.”
“He continues to focus on himself and the health of his relationships,” the friend added. “He attends meetings, many meetings, and he also does meditation and yoga.”
“While he still has his moments — and let’s be honest, everyone struggles — he continues to work hard on himself.”
This is the third time Affleck has been in rehab. The first time was in 2001, and in March last year, Affleck announced in a Facebook post that he had completed treatment for alcohol addiction.
“I have completed treatment for alcohol addiction; something I’ve dealt with in the past and will continue to confront,” he wrote. “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.”
Affleck and Garner filed to end their 10-year marriage on April 13, 2017, a year after they first announced that they were splitting up.
If you or someone you know is in need of help, please contact the SAMHSA substance abuse helpline at 1-800-662-HELP.