It is difficult to say much about how our future relationship might work when we don't know each other. Thus at this point, the possibility that we are not traditionally compatible and we won't necessarily agree on major issues is to be taken into consideration.
As a minimum, and assuming we don't get along terribly well (look around you -- it is a fairly common situation in traditional families), I'd be happy to meet the child and have an amiable long-term (but, if necessary, distant) relationship with you and your family, but I can't afford to take on the parental responsibilities that come with your child.
I am a scientist and a teacher. Half of my life is about going where no one has gone before. The other half is about shaping young minds -- giving them courage and knowledge to go where I can't. While I won't spend much time with your child, I may be able to advise and influence in the same way I do with David or my students.
Sure, this is a minimum. There can be more, if we get along and spending time together makes life better for both.
I guess this is the fundamental difference between marriage and this family model - in marriage, you agree to stick together in any situation and separation is seen as a catastrophe. Here, you only meet if you like to and the possibility of leading completely separate lives is considered as a reasonable alternative.
First and foremost, co-parenting is about the children involved -- we are talking about a parenting relationship aiming to help them live up to their full potential. I'm willing to contribute what I can -- with making them come to life as the biggest hurdle. Further along the way, I think i can make some valuable contributions to their education if you are willing to share life to a certain extent.
People are different, and so there is no one best way to co-parenting. Happy to hear from you and discuss your views on the matter.
We can look in the literature for examples of Co-parenting. A few examples that come to mind are
-- a married couple (don't have to be separated)
-- legal guardians of a child, even if not the original parents.
-- a gay or lesbian couple raising a child
-- some other group of people who share parenting duties
-- The British Royal Family. The Queen has parenting rights over all her children and grandchildren.
-- members of a Jewish Kibbutz raising children jointly
-- a polygamous family ( African Masai or old Mornon in Utah)
-- a Tibetan family where 2 brothers marry the same woman
-- a family group composed of 2 gay men and 2 lesbian women
-- a group of friends raising children together
-- polyamorous groups
It is not clear if it could include grandparents, god-parents, teachers, friends, social workers, orphanage employees and other people involved in parenting.
Maybe we can look for inspiration at the co-parenting agreement that would come in force between the late Prince Phillip and Queen Elizabeth in case of a divorce.
While the Queen never divorced, her son, Prince Charles has divorced Lady Diana. The non-royal has remarkably few rights and obligations towards the children after divorce.
So.... let me treat you like a Queen.
We can have the standard co-parenting agreement that would apply to the Queen's children from her extramarital affairs or to the Prince Consort after a divorce.