God does not have jealousy in the same way humans do. Human jealousy can be selfish or petty. That is not true of God.
The phrase a jealous God shows that God is unique and demands exclusive worship (6:15; Leviticus 10:2; Numbers 16:35). He alone is worthy of worship. He will not share his glory with idols or false gods.
The Hebrew word can mean “jealous” or “zealous” (strongly committed). It describes God’s deep commitment to his own honor and rule. God actively protects his reputation as the ruler over all.