Shocking details emerge on Jennifer Garner's history with Ben Affleck's new girlfriend

Shocking new details are coming to light about Ben Affleck's history with his new girlfriend Lindsay Shookus. As it turns out, she may not be a new girlfriend, after all.

As reported by People, sources close to Affleck's ex-wife Jennifer Garner say that Affleck after had an affair with Shookus during their marriage back in 2013 -- a full two years before the A-list couple publicly announced their separation.

SEE ALSO: Ben Affleck is all smiles with Lindsay Shookus on casual dinner date: See the pics!

Not only that, but Shookus was also still married at the time. She split from Kevin Miller in 2014, a year after she reportedly started seeing Affleck. Miller and Shookus were both producers on "Saturday Night Live" together.

Garner reportedly found out about Affleck's affair in 2015, two years after it started, and she confronted Shookus about it during a trip to NYC.

See photos of Jennifer Garner and Ben Affleck together:

Though sources close to Affleck and Shookus contend that Jen and Lindsay "do not have any relationship," a Garner source counters that "Lindsay refused to back down or quit the affair" after the confrontation.

If Garner did indeed find out about the affair in 2015, that would place her realization in the same year that Affleck's reported affair with their family's nanny, Christine Ouzounian, came to light. In other words, Affleck may have been having two affairs at the same time.

The "13 Going on 30" star also allegedly talked to Shookus' ex, Miller, following an appearance on "Late Night with Seth Meyers." Garner approached Miller, who is a supervising producer on the late-night talk show, backstage after his split from Shookus to have a conversation and show him "proof" of the affair in the form of text messages between Affleck and Shookus.

The jaw-dropping details come after Affleck and Shookus have taken their relationship public, stepping out together three times in less than a week for a series of coffee and dinner dates.

See photos of Lindsay Shookus:

Though initial reports indicate that the pair were in the "early stages" of their relationship, this new information would directly contradict those details.

Affleck and Garner announced earlier this year that they would be officially filing for divorce, almost two years after initially announcing their separation. Throughout those two years, numerous reports surfaced that the former couple was trying to rekindle and work on their romance as Affleck continued to live in their pool house.

Jennifer Garner and Ben Affleck share three children together and were married were 12 years.

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