True jealousy [1] is never kind or understanding, which is why when you’re confronted with it, it's typically mean, bitter, and just plain hurtful. But looking past the anger, and finding ways to deal with someone else’s jealousy can be very productive. To see my tips on how to do just that, .

• Remind yourself over and over again that their negative attitude comes from a place of jealousy and insecurity; it doesn’t mean that there's anything wrong with you.
• If someone is unjustifiably angry with you, the natural impulse is to lash out and get defensive. But whatever you do, don’t attack back. It will only serve to fuel the flames, and in the long run, it’s not likely to make you feel any better.
• Instead, kill ‘em with kindness. Once they realize that they can’t break you, they’ll eventually accept defeat. Plus, personally I find nothing more satisfying than knowing I was the best I could possibly have been in a conflict.
• Even though we don’t always like to admit it, often the frustration we feel when we’re attacked by someone stems from the truth we find in their words. It’s certainly not always the case, but if you find it to be true in your situation, instead of getting angrier, try working on yourself. No one can ever find fault in people who make an effort to improve themselves.

If all else fails, just ignore them and remember that it's their problem, not yours.

Source [2]