Six months after Jennifer Garner and Ben Affleck announced they were splitting, the Gone Girl actor, 43, continues to live in a guesthouse on the family's Los Angeles estate.
And while the two appear to have an amicable relationship – even spending Thanksgiving and Christmas together as a family – a source says that both Affleck and Garner, 43, are discovering that living with an ex can be rather challenging.
"It's obvious many times that they both find it annoying to deal with each other," an insider tells PEOPLE in this week's issue. "Understandably so. It's a strange situation to live together and yet be separated."
For more on Jennifer Garner and Ben Affleck's co-parenting style, pick up the latest issue of PEOPLE on stands this week
But the couple is willing to put their differences aside to do what's best for their three children, Violet 10, Seraphina, 7, and Samuel, 3.
"They both seem to find the situation frustrating, but for now at least, they also seem to think it's best," says the source.
"They are doing what is working for the kids," adds a Garner source.