My wife's wandering eyes towards my brother

Hi, me and my wife married for 2 months now. We had an arranged marriage. At first she rejected my brother's match and liked my match and she really liked me and loved. We were happy. I work in night shifts and a less paying job than my brother. Where he works for a good company and travels to clients place for every 2 months back and forth. Me and my wife living in there house for 2 weeks now. I am noticing frequent eye glazes between them. My wife doing it when I am not looking at her. She is a social nervous and shy person. I don't know why she is doing that, I am more attractive than him in all possible ways. Am I over reacting, feeling insecure? This is killing me , what should I do? Please help.