Rumor had it Phillippe's co-star Abbie Cornish was involved in the breakup, which was made official when they divorced in 2007.
It was an adaptation of Choderlos de Laclos's Dangerous Liaisons made for Generation Y.
He recalled a visit the four shared while Witherspoon was in New York City promoting both Gone Girl and Wild: "We got to meet up as a family and took a walk through Central Park with the kids.
And it was funny -- we were reminiscing then because we shot a lot of Cruel Intentions [there], so there we were with Ava and Deacon talking, and they were tripping out on the fact that we were there shooting a movie before they were even a thought in our minds.
"I was just kind of floundering career-wise cause I wasn't making things I was passionate about, I was just kinda working.