Ben Affleck cheating was reportedly the last straw why his 10-year-old marriage to "Alias" alum Jennifer Garner crumbled.

According to People, a source declared, it was in late June when the family went to the Bahamas for a long-planned holiday that then married couple Ben Affleck and Jennifer Garner were trying to determine what to make out of their future together.

"It was game time," the source said. "Ben had already told her he hadn't been committed to the marriage. They were trying to figure out what to do."

It was also revealed by a handful of sources that Garner discovered during their stay in the Bahamas that the "Batman v Superman" star was cheating on her with the kid's baby-sitter, Christine Ouzounian for months. (Ben Affleck has strongly denied the allegations.)

A friend disclosed, "There was always a speck of doubt in Jen's mind about separating, but that's now gone."

"She is very angry. To Jen, this is the ultimate betrayal."

So, who is Christine Ouzounian in the life of 'Batman v Superman' actor Ben Affleck?

Christine Ouzounian was employed as a nanny by the couple last spring and "was very caring and loving towards the kids," according to a L.A. source. She has also worked for "How I Met Your Mother" actor Neil Patrick Harris — Ben Affleck's co-star in "Gone Girl."

The source added that Ouzounian showed an increased interest and attention to the "Argo" star/director, and was "dressing a bit more inappropriately" around him when Garner went to Canada to start filming "Nine Lives."

A source close to Ben Affleck, according to Radar Online, defended their closeness and said, that what they have was "a work relationship and a friendship. Ben's friendly, but it's not always meant to be flirty, and this was a very close relationship with someone who was taking care of the most important people in his life."

However, 28-year-old Christine Ouzounian apparently dished out to friends that she was hooking up with the actor.

"For Christine, it was a real relationship," a source detailed, as per People.

"They had even talked about plans for celebrating his upcoming [Aug. 15] birthday."  

Meanwhile, photos of the talented actor meeting up with the ex-nanny of his children surfaced on the web only days before his split with Jennifer Garner.

As The Daily Caller detailed, the snap taken on the night of July 17, showed the "Daredevil" star walking to meet Christine Ouzounian who gifted him a champagne bottle outside his rented home.

Stay tuned for more updates on Ben Affleck's cheating scandal. Do you think the "Batman v Superman" actor had an affair with nanny Christine Ouzounian? Sound off below.