Jealousy in the Bible confuses many people. God tells us that jealousy is bad, and yet somehow, the Bible makes it abundantly clear that God Himself is jealous. How can jealousy be evil, and yet at the same time be prevalent in the Holy One? The answer is surprisingly simple. It depends on what one is jealous over. It is evil when one is not entitled to the thing one is jealous over, but it is not evil when they are.
Imagine two men. Both of them are jealous for the same woman, but one of them is married to her. The married man has every right to be jealous for his wife. Seeing another man kiss her would rightly make him quite angry, and he has the right to defend her. This is a jealousy the married man is entitled to. The other man, by contrast, is not her husband. He is jealous for something he has no right to be jealous for. It may upset him to see her husband kiss her, but imagine if he tried to intervene. "How dare you kiss my wife?" and "how dare you kiss your wife?" are two very different questions.
As the owner of literally all created things, God has the absolute right to be jealous. And, in the case of Paul in 2 Corinthians 11:2, His servants have the right to be jealous for that which is dedicated to, or prepared for the Lord. Jealousy is a good thing when applied correctly. Be jealous for what is yours, but never for what isn't.