Affleck, 46, was spotted on a dinner date with Sexton, 22, at Nobu in Malibu on Tuesday, August 16.
"Ben seemed like he was in a somber mood," a source told Us Weekly. "He comes in from time to time."
The actor came in with a "big team" and "bodyguards all around."
"He sat outside with Shauna, and they got a lot of food," the insider spilled. "Ben arrived by himself and left by himself in his car. He tipped the valet with a $100 bill.
The outing sparked rumors that Affleck and Shookus, who went public with their relationship in July 2017, split.
The couple was last spotted on a trip to Puerto Rico in July.
Radar previously reported in July with Affleck and Shookus planned to tie the knot.
"They want to do it before end of summer when Lindsay goes back to work on SNL," an insider told Radar. "They love Hawaii and had a great time there in April when Ben was filming Triple Frontier."
Affleck split from wife Jennifer Garner in 2015 after 10 years of marriage. They share children Violet, 12, Seraphina, 9, and Samuel, 6.
Do you think Affleck and Shookus split? Tell us in the comments.
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