Having a
baby
boy may be new territory for
Jennifer Garner and
Ben Affleck – but they're
overjoyed to be parents for the third time.
"Jen is feeling good," a
source tells PEOPLE. "She's so thrilled to have a little boy, and the girls
already love him so much."
Their
son Samuel
joins big sisters
Seraphina, 3, and
Violet, 6.
While the actress
told Ellen DeGeneres that "it
would be so weird to have a boy," Garner seems to be taking it all in stride.
"Jen is such a natural mother," says a source close to the couple.
The
proud
parents, both 39, have always put family first.
"He couldn't be
happier," Affleck's friend tells PEOPLE. "He loves his wife. He loves his family
and he's proud – he's legitimately proud – you can just see it."
As for
Affleck, who has been acting less to focus on directing lately, his most
important role is being a father.
"He's gets to spend a lot of time with
his family and the idea that they have three kids right now is something that
makes them both feel really good," the source adds.
The couple, who
wed in June
2005, announced they were
expecting their
third child in August.
For more on Affleck and Garner's growing
family, pick up the latest issue of PEOPLE, on newsstands Friday.