My lawyer summed it up as: to get primary custody, she has to show she's a good mom. For me to get primary custody, I have to show I'm a good Dad and she's a bad mom.
What is your jurisdiction?
Courts these days WANT to grant 50/50, it's no longer the case in most places that you have to prove the other parent unfit. Neither of you needs to be "primary" (one WILL be for the purposes of legal definition, but joint physical and legal custody is the norm).
Do NOT let this three weekends a month crap become the norm, courts LOVE status quo.
