Yeah, "The One with Mrs. Bing"
N if we're going with lighthearted cuckolding, there's Leonard's mom in The Big Bang Theory..though that's only borderline lighthearted.
She abused her son pretty much from birth, treating him like a science expert instead of a son. She made him feel worthless even when he was the top of his field, and I'm pretty sure I remember her cockblocking him when he was younger.
N that was all before episode 1
Then she showed up, n showed far more affection for his best friend, than she ever had him, and was constantly having intimate, personal conversations behind her son's back.
Then humiliated her son by implying he wasn't able to satisfy his girlfriend, while also insulting his father by saying he was never able to satisfy her. All while talking about her wildest sexual fantasies in front of him.
And then, in front of her son, she made out with I his best friend, and not only did neither of them ever apologise to him, but neither of them ever felt a shred of guilt over it.
(and if you wanna stretch it, this was after his best friend cock blocked him by stopping him giving highly classified military secrets to a North Korean spy, which would of absolutely been worth at least a blow job)
Oh, and I'm pretty sure Leonard's best friend saw his crush's tits before he did, and groped them.
Honestly there was a LOT of cuckolding in The Big Bang Theory if you loosen the term even a little, and some that was bang to rights cuckolding.