Ben Affleck 'Wants the Best' for Jennifer Garner as She Starts Dating After Divorce

Ben Affleck has no hard feelings now that Jennifer Garner is "casually dating" businessman John Miller just three weeks after finalizing her divorce.

"Ben will always want the best for Jen," a close friend of Affleck's told PEOPLE. "They continue to have a really strong relationship and both work very hard to make everything easy for the kids. She has always been supportive of him."

Reports that Garner and Miller were a thing first broke Wednesday, with a source telling PEOPLE that the couple have "been together six months — and it's getting pretty serious."

"Jen brings out the best in John, and he is the happiest he has probably ever been. It's a loving, healthy relationship," the source added.

A second source revealed that Garner and Miller, the CEO of CaliGroup, are "at similar places in their lives," their relationship kickstarting after they "met through her group of friends."

Miller, who was also previously married, has a 12-year-old son and 10-year-old daughter, while Garner shares daughters Violet, 12, and Seraphina, 9, and son Samuel, 6, with Affleck.

Prior to the reports of the newly fledged couple, it had been reported that Garner was eager to get back into the dating game and had "been wanting to move on" for some time.

Garner isn't the only one to have moved on. Following their initial separation in June 2015, Affleck entered the dating pool, starting relationships with Saturday Night Live producer Lindsay Shookus and Playboy model Shauna Sexton. Affleck later reportedly ended his relationship with Sexton in order to focus on his sobriety, his recent stint in rehab being one of the reasons that Affleck and Garner's divorce finalization was postponed.

"Jen wanted to give Ben the time and opportunity to work on his health and sobriety," a source said. "She isn't in a rush...Jen just isn't willing to settle the custody issues until she's 100 percent certain that he's clean."

The former couple had married in 2005 before simultaneously filing for divorce in April 2017 following their 2015 split.

"After much thought and careful consideration, we have made the difficult decision to divorce," they said in a statement at the time. "We go forward with love and friendship for one another and a commitment to coparenting our children whose privacy we ask to be respected during this difficult time. This will be our only comment on this private, family matter. Thank you for understanding."

Affleck and Garner finalized their divorce earlier this month with a private judge at Garner's residence.