I read some definitions about "envious" and "jealous" but still not sure which has more positive implication and is common used in conversation. If you were me which would you choose? For example, if you're a bachelor and your friend get married to a very cute lady, but you're really happy with that.
The Motivated Grammar blog has this useful summary:
Envy is pretty well restricted to the feeling you get from wanting someone else’s stuff. Jealousy is a bit more inclusive, allowing you to either want to have someone else’s stuff or want to keep your own stuff.
Grammar Girl, however, dispenses this caveat:
The trouble is that “jealous” and “envious” have overlapping meanings and are often used interchangeably, but some people argue that they mean different things.
If you wish to be precise, make a distinction between “jealous” and “envious” in your writing, but don’t be surprised when the definitions are blurred in pop culture.
My usage tends to agree with the one from Motivated Grammar; by that measure, it would be more positive to tell your friend, "I am envious of your good fortune."
I think you can in good conscience say you envy your friend, and it will be taken as a friendly remark. I don't see jealous as quite so innocent, but in general there isn't much to differentiate the two terms. For example, wiktionary usage notes for jealous say
Some usage guides seek to distinguish “jealous” from “envious”, using jealous to mean “protective of one’s own position or possessions” – one “jealously guards what one has” – and envious to mean “desirous of others’ position or possessions” – one “envies what others have”. This distinction is also maintained in the psychological and philosophical literature. However, this distinction is not reflected in usage, as reflected in the quotations of famous authors (above) using the word jealous in the sense “envious (of the possessions of others)”.
When taken to extremes, neither envy nor jealousy is a positive emotion; for example, envy is known as the second deadly sin. But if you are envious or jealous, to say otherwise would be lying, which generally is not recommended except in social situations where the truth will offend.
If I were forced to differentiate between the two in your particular example,:
I'm envious of you could just mean that you are envious of him getting married - and that you would like to get married.
I'm jealous of you could mean that you would have liked to marry his wife.
Note that these are not definitive answers, and context (or tone of voice) can considerably affect the implied meaning. Also, as others have said, there is considerable overlap,, and people may use them in different ways.
Both envious and jealous have similar definitions:
Compact OED defines envy as
a feeling of discontented or resentful longing aroused by someone else’s possessions, qualities, or luck
It defines jealousy as the state of being jealous and defines jealous as
feeling or showing an envious resentment of someone or their achievements, possessions, or perceived advantages
While they can often be interchanged, jealous can also be used to refer to a guarding of ones own possessions or rights. COED offers
feeling or showing a resentful suspicion that one’s partner is attracted to or involved with someone else: a jealous husband
fiercely protective of one’s rights or possessions: the men were proud of their achievements and jealous of their independence
(of God) demanding faithfulness and exclusive worship.
While both envy and jealousy are usually fairly negative emotions, in American English the phrases "I am envious of you" or "I am jealous of you" can be used to express an admiration of the position of the listener. More frequently, the phrase "I envy you" would probably be used.
Perhaps a better construction, to emphasize the positive aspects of your views, would be "I admire you".
The important thing to keep in mind is as follows: jealousy is triggered by a third party. I'll say it again: jealous feelings are triggered by a third party.
Let's modify the example you gave by adding the following component: you are very much attracted to your friend's wife. If your friend finds out about it and sees you chatting up his wife, he would likely display a measure of jealous behavior.
On the other hand, let's keep your example as it is. You say your friend's wife is "a very cute lady." Fine. Of you it could be said, "You're a little envious!" In other words, you might want (deep in the recesses of your unconscious mind!) what is not yours to have. Envy, by the way, is called the "green-eyed monster." Another saying is, "The grass is always greener on the other side of the hill." But I digress.
True, there are three parties involved in both of the above scenarios, but what triggers jealous feelings is one party's right (within reason, of course) to protect the third party (i.e., his wife). Your friend does NOT want to share his wife with another person--even you, his good friend. This is normal.
Jealous feelings get out of hand, however, when a husband becomes so suspicious of his wife's behavior, that every time she talks to another man, her husband flies into a jealous rage. Clearly he is overreacting (if in fact his wife is simply talking with another male in the normal course of events). Maybe she's just asking a guy for the time!
Jealous feelings can become a cancer in a committed relationship, because a critical element in the foundation to a good marriage is trust. When trust evaporates, jealousy rears its ugly head.
Being envious can also be destructive, like a cancer. An envious person is never satisfied with what she has but is forever gazing enviously on the abilities, gifts, possessions, and good looks of others. Contentment eludes her.
Which has a more "positive" implication? Offhand, I'd say neither.
Nevertheless, it is perfectly acceptable in normal conversation for you to say to your friend in a friendly, non-threatening way, "Hey man, I'm really envious of your for marrying such a great gal! I hope I do as well as you did when the time comes for me to marry!"
I've noticed that people today use the terms envious and jealous almost interchangeably, which is OK, I guess. If they use the word jealous, however, usually they mean envious, and when they use envious they could mean jealous.
Is it worth correcting people when they mix the two words up? If you're the teacher and they're the students, then OK; otherwise, just pride yourself on knowing the difference between the words envious and jealous and keep this knowledge to yourself!