Do natives misuse "jealous" and "envy" a lot?
There're many web pages tell the differences of them; 'Jealous' is used when you describe you being anxious about something you have being taken away. And the 'envy' is the opposite.

But in the fan fictions or web comics I have read so far, they used those two words completely other way around. All of them at that. So I was wondering how often do natives misuse them.

Question

Do natives misuse "jealous" and "envy" a lot?
There're many web pages tell the differences of them; 'Jealous' is used when you describe you being anxious about something you have being taken away. And the 'envy' is the opposite.

But in the fan fictions or web comics I have read so far, they used those two words completely other way around. All of them at that. So I was wondering how often do natives misuse them.

Answer

You’re probably wrong to think that people are misusing the words. The differences aren’t as you describe. Very roughly, “jealous” can be used in the place of “envious” and often would be. Jealous has an additional meaning, which usually has to do with relationships.

I am jealous of his success.
I am envious of his success.
I envy his success.

I get jealous whenever my wife has lunch with Jim. (Can’t use “envy”)

Answer

Often yes, but it also is about educational levels even with natives.

Just be wary of using fanfiction as a source.  The quality varies significantly.

Answer

jealousy has to do with intimate relationships, and envy has to do with feelings of insecurity towards others, but yes many native speakers use them interchangeably.