Pic: Bachelor Ben Caught Cheating

The evidence is undeniable.

He may have gotten engaged to Courtney Robertson in Switzerland last November (in a dramatic proposal which aired on the March 12 finale of Season 16 of "The Bachelor"), but that didn't stop Ben Flajnik from stepping out on his bride-to-be -- with three different women in one weekend in mid-February in San Francisco.

PHOTOS: Stars caught cheating

During the emotional "After the Final Rose" special,  Flajnik, 29, adamantly denied groping and making out with one particular woman by a waterfront park near the Golden Gate Bridge -- but Us Weekly has the photographic proof, taken just before midnight on Feb. 18.

Says one insider who witnessed Flajnik's kissing: "Ben did not seem to care who saw him, considering his status on a prime-time reality show about finding true love."

In fact, that was the third of Flajnik's flings over one very busy weekend. On Feb. 17, Flajnik -- out with a group of four ladies -- was feeling especially frisky, chatting with several women who came up to him at local haunts Monaghan's and the Lion's Pub. When two of them set their sights on Flajnik, he pounced. "Ben seemed pretty toasted, and this woman in red pants came up to him," says a witness. "It looked like an altercation at first, then he kissed her on the mouth and hugged her."

VIDEO: Courtney apologizes to Ben's bachelorettes for her bad behavior

When that woman split off from the group, Flajnik and his friends continued on to a local donut shop with the remaining women -- one of whom had been texting with Flajnik since they met on Valentine's Day, according to a source. After picking up a dozen pastries, Flajnik and the group walked the few blocks back to his apartment.

VIDEO: Courtney flashes her boobs in Panama

"Ben and this girl looked like they were drunk and having a good time," says a witness of Flajnik and his gal, who spent the night at his place and surfaced the next morning wearing the same clothes as the night before. "They were doing weird dance moves, laughing and joking."

But during the "After the Final Rose" special, Flajnik swore all three women were just "long time friends,"

Tell Us: Are you shocked by Flajnik's denials?

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