"for you shall not worship any other god; for the Lord, whose name is Jealous, is a jealous (impassioned) God [demanding what is rightfully and uniquely His]" - Exodus 34:14(AMP)
Firstly, you need to establish what jealousy is from God's perspective. God is a Jealous God. His name is Jealous and the above verse establishes that. When God created man, He did so in His image and likeness. This means that God's expression of His emotions and feelings is exactly what is mirrored in man. His emotions are an intricate part of who you are. Anger, hate, jealousy, and other emotions that are termed negative are all emotions God Himself expresses. Therefore, He put them all in you.
God could hate Esau and yet be without sin (Malachi 1:3, Romans 9:13). He could express His anger and remain holy. He is jealous, and yet righteous. God expects expects the same of man. It is what He had in mind when He created man in the first place - to be like Him. Unfortunately, the fallen state of man makes this impossible to achieve because when man fell, corruption entered into the world. One of the results was to corrupt these emotions. They no longer stemmed from the pure and holy source (i.e. God Himself), but had its source from the flesh - the corrupt nature of man. This is why whenever you feel jealous over something(s) or people, the natural tendency for you is to react with evil.
19 Now the practices of the sinful nature are clearly evident: they are sexual immorality, impurity, sensuality (total irresponsibility, lack of self-control),
20 ldolatry, sorcery, hostility, strife, jealousy, fits of anger, disputes, dissensions, factions [that promote heresies],
21 envy, drunkenness, riotous behavior, and other things like these. I warn you beforehand, just as I did previously, that those who practice such things will not inherit the kingdom of God. - Galatians 5:19-21(AMP)
The above scriptures clearly confirms the source of man's jealousy - the flesh. Therefore, the only way to deal with jealousy is to counter the desires of the flesh by walking in the Spirit! As a believer, you establish who God is to you by walking in the Spirit. You need to receive God's available grace so as to live above your fleshy desires. Ask yourself pertinent questions like how jealousy towards someone or something produces God's righteousness. Is your jealousy a God-fruit? Would God be pleased with you being jealous? The answers would help you clearly see how God views the jealousy of man, and what you need to do whenever that emotion rears itself up. The work of salvation in you is to replace the sin nature with the God-nature. But as long as you are in this world, having a physical body, there would always be that contention for your soul. Hence, emotions stemming from the flesh would always struggle to control you.
16 But I say, walk habitually in the [Holy] Spirit [seek Him and be responsive to His guidance], and then you will certainly not carry out the desire of the sinful nature [which responds impulsively without regard for God and His precepts]. - Galatians 5:16(AMP)
It is therefore your duty to rely, submit and trust the Holy Spirit to produce good works and God-fruit in you. Doing this brings your flesh under subjection to God, and this includes your emotions. Your emotions become as pure as God's own emotions such that whether your express anger, jealousy, love, hate, or anything else you would be doing so with a pure heart, in righteousness and without sin. The more you dwell on the things of God such as praying, reading, studying and meditating on His word, the more you respond to things by/in the Spirit of God; the more the works of the flesh have no hold over your life. You would just notice that the petty things which evoked the wrong kind of jealousy are no longer there. If at all you become jealous, you would be jealous of the things of God i.e. expressing the God-kind of jealousy. Your heart would begin to fill up with love, meekness, peace, patience and other God-gift. This is how you deal with jealousy.
Have a blessed week!