I think jealousy is when you covet something of another person’s, and just want to have it yourself. Envy is when you don’t care if anyone else gets it too, you want that for yourself (a bit more generous).
Jealousy is a problem when it helps you make bad life decisions, and when you start losing friends and people lose confidence in you because they question your motives. When you can’t enjoy a friendship or a movie or anything life has to offer just you. When your actions from jealousy hurt others, and limit you emotionally and physically.
I personally believe we all get jealous on occasion, it’s human nature, but acting on it is the problem. For example, if you’re jealous but keep it to yourself and the feeling fades, replaced by admiration, nothing wrong with that. But if you’re jealous and start plotting someone’s ruin, that is not good.
Envy is not so bad either, so long as you can channel it into self-improvement and make it a positive motivator for yourself. sorry if I’m rambling, I think I need a break from the computer