It was a joke from Eddie Murhy's stand up act
I have never believed in cheating.
I'm not sure if it was Eddie Murphy's RAW video, but he once did a stand-up routine about how a woman will forgive a man
ANYTHING, as long as he could make her orgasm like there was no tomorrow. I remember watching that video with my girlfriend "A", and our other girlfriend "B" and "A's" boyfriend "C". It was soooo hilariously funny, because just one week before "A" had caught "C" upstairs in "B's" apartment. She had forgiven them both. "B" used to avail herself of "C's services", and bragged about his skills to "A". "A" who had just dumped her boyfriend, and was feeling particularly lonely one night, decided to give "C" a late-night booty call at "B's" suggestion. "B" thought it was just the tonic "A" needed. "C" gave it to her soo good, next thing you know, she was moving him into her apartment. Even though "C" had now moved in with "A", "B" didn't see any reason to deprive herself of "C's" services, ...afterall, ...she had discovered him, so their occasional trysts continued for close to a year, unbeknownst to "A". And when she discovered it, "A" couldn't bring herself to throw him out thereby depriving herself as well, ...so all was forgiven on the stipulation that "B" & "C" kept their hands off each other.
We were all sitting around watching this video, everything forgiven & forgotten. "A" had forgiven "B" & "C". I had forgiven "B" for her betrayal of "A", and there we were all laughing together uproariously, ...just like old times, ...when Eddie delivers the line saying
"All you have to do is to give it to her reeeeeal goooood, ...make her moan like OOOOOOOOOOOHHHHHHHHHHH.. . and she'll forgive you anything. Get caught sleeping with her best friend? No problem... if you can make her come like a runaway locomotive... she'll forgive you." 
As soon as he uttered those lines, ...the entire room went so quiet, you could hear a pin drop.

"A" grabbed the remote control, and flipped off the VCR, while "B" & I tried desperately not to burst into laughter. "C" cringed in his seat, avoiding any eye contact at all, pretended like nothing had happened, but he was terrified to even look in "A's" direction.
The sad part is... it's often true. If a guy knows how to work it, ...he can sometimes get away with murder.