Jennifer Garner has been a total rock for Ben Affleck as he navigates his marital crisis with Jennifer Lopez — and sources exclusively tell Life & Style his ex-wife even offered him the chance to move in under the same roof.

“He’s got a key to come and go as he pleases, and he’s been spending a ton of time at her place, coming over for dinners and hanging with the kids,” an insider says of the Oscar winner, 51, who shares children Violet, 18, Fin, 15, and Samuel, 12, with the Family Switch star, 52.

“It’s great for his state of mind and the kids love having him around,” adds the source, noting that’s been a big reason “why Jen’s open to the idea of having him move back in.”

The 13 Going on 30 actress — who has been dating CaliGroup CEO John Miller for six years — has got “a ton of space,” says the source, “so he wouldn’t be in her way, and she knows it would bring a lot of comfort to their kids.”

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In Touch was first to report last month that Ben and the “Let’s Get Loud” singer, 54, are “headed for a divorce” and that he moved out of their martial home. (Neither have publicly addressed the split rumors, though Ben has been seen without his wedding ring on while J. Lo was thousands of miles away vacationing in Italy.)

The actor’s ex-wife “hates the idea of him being all alone when he’s going through such a painful transition,” explains the Life & Style source.

Despite the turmoil, Ben is committed to maintaining his sobriety — and has the support of his loved ones. “He’s going to his AA meetings and getting tons of support from his friends, but Jen’s still very protective of him and wants to do anything she can to make this time easier for him,” says the insider.

Ben and J. Lo, who married in July 2022, have been living apart as they inch closer to splitting — and it appears Jen Garner is doing all she can to make the transition as comfortable as can be.

“Ben’s not short on money, but he’s not really looking to move into a hotel; it’s just too anonymous for him,” says the Life & Style source. “He could go to another luxury rental but considering all the time he’s spending at Jen’s place anyway it makes sense to just take one of her guest rooms.”

While it’s clear that Ben and his ex-wife are getting closer amid the drama, “There’s absolutely no hanky-panky going on between them,” says the insider. “She’s still very happy with John, this is just about her wanting to keep a closer eye on Ben, helping him out and doing what she feels is best for her kids.”

A source recently told In Touch that “Jen’s been wonderful” throughout the entire ordeal. “She doesn’t judge,” said the source. “Sure, Ben drives her crazy sometimes, but there’s an unbreakable bond there. Ben says Jen’s an angel and tells her she’s the only one who can save him.”