Yes, there are. The concept of cuckoldry often involves themes that can be considered disrespectful and unethical in relationships. It can promote feelings of humiliation and violate the privacy and dignity of those involved.
Well, in some cultures, the idea of cuckoldry might be seen as a complete taboo as it goes against the traditional family values of fidelity and respect. It could be seen as a deviation from the norm.
There are no positive aspects. This kind of comparison is inappropriate in the context of human relationships. We should promote respect, love and equality in relationships, not such vulgar comparisons.
In general, they are not considered ethical. While literature can explore complex and controversial topics, cuckold cock sucker stories often cross the line into promoting behavior or situations that are not acceptable in a healthy, ethical society. They can also be demeaning to the characters involved and send the wrong message to the readers.