First link:

the husband of an unfaithful wife.

Agrees with me.

Second link:

"a man who is aware of and complaisant about the infidelity of his wife; a contented cuckold."

Talks about the sexual fetish cuckolding and the use of the term as a general insult:

Cuck is often used by conservatives to insult liberal men for being weak or effeminate.

It's like saying gay doesnt mean homosexual because its frequently used as a generic insult. Clearly the use of the word gay as a generic insult doesnt change the meaning of the word, it just means the word is frequently used as a generic insult due to previous and current homophobic tendencies of society.

Just as the use of the word cuck as a generic insult is because it is considered effeminate/unmanly to have a wife that cheats on you.

So this article is almost exclusively about explaining the tendency of cuck to be used as a generic insult, it's not about the literal meaning of the word.

Third link:

A cuckold is the husband of an adulterous wife

Agrees with me.

Fourth link is literally urban dictionary and its laughable to even bother mentioning it, the definition upvoted on there by 1600 random people on the internet is also about the sexual fetish cuckolding which is its own thing, its the fetish. Context matters.

So it appears your links does agree with me.