Your feelings are not bad or wrong. In any relationship, communication is key. I think it is important that you have a calm conversation with your wife regarding your concerns.

Jealousy could also imply disguised admiration. When you look at the emotion closer, you'll realize that often we tend to feel jealous toward someone who has a quality that we admire and would like to see as part of our own nature. This feeling that you experience when you see your spouse expressing love and affection toward her parents could also reflect how much you value it and admire it. Forgive me for stating the obvious, but speaking to your wife about how you feel and trying to understand her perspective would help lighten the burden of anxiety and worry.