I can answer only in terms of Indiana law. I'm unsure what state you're from:
You mentioned you were splitting up. Is it a marriage?
In Indiana, if you are not married to her, there's a putative father registry in which you go get registered. That can help keep her from adopting out the child without your permission.
If you're not married you are STILL entitled to visitation and parental rights. But you MUST establish paternity in order for those to be granted to you.
If you were married, then you are presumed to be the father and certainly have rights.
Parental contact w/a child is NOT at the whim of one parent; it is at the court's discretion. And courts like to have BOTH parents have a meaningful relationship with the child. Therefore, unless you're proven unfit, you will receive visitation and/or custody. And the same w/her.
Does this help at all?