When Ben Affleck and Jennifer Garner separated in 2018, we were devastated and didn’t know if they could ever become amicable exes. But, thanks to Jen’s new boyfriend, John Miller, the former husband and wife’s relationship has become a whole lot better!

“Jen having a boyfriend has been the best thing to happen to Ben and Jen in a long time,” an insider told Us Weekly, adding that “Ben’s become a better parent” too.

EXCLUSIVE: John Miller picks up groceries after reportedly cooling things off with Jennifer Garner.

“[Ben’s] really showing Jen that he can be a better person,” the source continued about the Batman actor who shares three kids — Violet, 13, Seraphina, 10, and Samuel, 7 — with the Alias actress. “They’re coparenting in a way they never have before.”

Now that they’re better coparents, Ben can be there for his kids whenever he wants. “He ultimately just wants to be the best father he can be and part of that is continuing a loving relationship with Jen,” the insider said. And the best part is that they all get along!

“Ben has no problem with John,” the insider admitted. Since Ben has reportedly been on and off with Lindsay Shookus, he couldn’t be any more happier that Jen found someone new. “No one would be surprised if they got engaged. John has discussed marrying Jen,” the source explained. Jen “admires John because he is just normal.”

Ben Affleck's family

The 13 Going on 30 actress doesn’t have to worry about her kids relationship with John either because his kids from a previous marriage have been having a great time going on “playdates” with Samuel, Violet and Seraphina. Plus Ben has no reason not to trust John. They’ve been getting along so well, which is hopefully allowing Jen to breathe the sigh of relief she so deserves.

“[He] totally trusts him,” the insider noted.

Looks like this trio have this whole coparenting thing down!