Why is she so concerned about me checking out other chicks while she has no real commitments outside of staying home with kids? ?

Ok. So what I mean by no "real commitments" outside of home life is that she occasionally invites her ex to help out with things for the house, goes out to lunch with friends or her baby daddy, or go to her swinger friends all the time so their kids can play. She gets to pretty do whatever because she doesn't hold a job or commitment to school or anything but has her son and our 3-month-old? Not to mention she uses Instagram, FB, etc and has online access all day long. But she is like obsessed that I check out chicks on the daily and fantasize about them, and I don't understand why she is so insecure about these things when she has so much more freedom in comparison to me. Is it her who probably messes around and is terrified or of me either finding out or losing the upper hand as she feels eventually I'll get her back? No idea.