LONG RANT, sorry.
The problem with all the old ways about custody and vistiation is that there is a built-in bias that interfgeres with the child's bonding cycle. (Because of the influx of post-institutionalized children into adoptive families, a great deal of well respected current research, about bonding and attachment is now available that court systems seem to be oblivious to). If the couple had been together when the child was born, BOTH parents would be able to assume all aspects of child care drom the beginning. Except breast-feeding, of course, but I know a number men who have fed their kids pumped breastmilk when mommy was at work or gone. Anyway, that means that the NORMAL family situation would have baby waking up to see Daddy's face nearly as often as mommies (at least among the nurturing couples I know who share childcare responsibilities, whether divorced or in intact families. Baby SHOULD be able to have the opportunity to develop a normal bonding cycle with Daddy as well as mommy.
Problem is twofold. If born outside the marriage Daddy isn't legally Daddy until paternity is established and our legal system has a dis-incentive to provide Daddy access until legal custody process is completed. So mommy maintains full custody in most cases until all the legal issues are dealt with. THen the courts say "Oh, well the child is used to being with Mommy (and all that tender years doctrine which is NOT backed up by any of the known research on bonding and is only a biased presumption that interferes with a child's normal process of bonding with Dadd)y.
I won't get into the scenarios in which woman have chosen to allow a pregnancy with some guy they claim is a scumbag (or a virtual stranger) and use this rational as a reason to deny access. In my mind, if he is either a stranger or a scumbag, WHY sleep with him in the first place, much less sleep UNPROTECTED.
Anyway, presuming this is a somewhat normal, but now broken, relationship, Daddy is still Daddy from birth and should have the same rights of access to HIS child that mommy does. Daddys are very important to kids. Just because mommy and daddy cannot be together does not mean mommy should rob baby of daddy.
And this silly presumption that somehow a first-time parent who happens to also have a uterus and breasts is automatically a superior parent to the other first time parent who happens to have genetalia instead is not warranted. I know many first time fathers who were fantastic parents. Every male in my large extended family is good with babies and very nurturing. Why should they automatically be disallowed their parenting time in equal proportion if they are equally responsible for that child's existance?
So anyway, by the time paternity is established and mommy and daddy get to court to deal with custody and visitation, the courts say: "Baby has been with mom", and then use THAT as their rational to limit daddy time!
Please understand that I am part of a large community of parents who totally missed out on being able to parent their child from birth. And having missed that time, and never being able to know what her babyhood was like, never being able to know what she looked like when born. or at six months or one year old, when she took her first steps, cut her first tooth, etc., will ALWAYS hurt. So perhaps I have greater sympathy for those who are denyed their parenting time when baby and dad COULD have had this baby time together. Also, because of the fact that in my "other parenting community" most if us first began parenting our children at anywhere from several months to several years old, I reject the idea that a child cannot handle a transition into a different household perfectly well at older ages. Status quo ALONE is not always a good reason to deny the OP custody. Personally, I do not believe staying with mom through a a variety of live-in boyfriends is any more stable than eventually living with Dad in a stable household, if that is the case. And I have seen many postings in which Daddy can offer a safe, secure environment, and mom chooses (I'd say "Gypsy", but because I have a Roma child I do not wish to perpetrate a negative stereotype) less stable lifestyle with a variety of instable relationships and she retains custody, despite the fact that the child may be poorly served in such a scenario, because of status quo and the silly preesumption that a poor continuous environment is preferable to a superior, changed environment.