I personally do not think 50/50 is necessarily a good thing. I would have hated it as a child, I would hate having to do similar as an adult, it would not be the right thing for my children and I would fight hard against it.
When we did 50/50 it was all in my home (XP was homeless) which suited the kids fine, but it imploded for a variety of reasons. XP now lives too far away even for basic contact visits, but if it was hypothetically on the table I would rather be the NRP than the children have to do 50/50.
I absolutely wanted to co-parent with him, unfortunately he saw this as me "using" him, and felt that as it was my decision to end the relationship the children were now entirely my responsibility. He used his contact with the children to punish and control me, and he absolutely damaged our eldest just as much as if I had withheld contact. Yet if he took it court, this would likely be ignored in favour of giving him another chance because of their right to a relationship with him. And I don't even have the option of taking him to court first, however expensive an option that may be. Because he isn't seeing them, I have nothing to seek a court order for, so I just have to wait and hope that his new family is enough distraction for him. I have spent over 6 months chasing him to see them, and now I am done and I would like some legal closure on it. I don't want him punished for "missing material possessions", I want him punished for the damage he has done to them and I want him kept as far away as possible so he never has the chance to do it again. There are no consequences for what he's done.
Aside from that, if 50/50 is what is going to be used as a base mark upon separation then surely it has to be from the point the baby is born? If one parent has given up their job and career progression due to a mutual decision for them to be the main carer (and in the process enabling the other parent to maintain their career progression by the provision of free and flexible childcare) then that parent absolutely should be compensated for their financial sacrifice by the other parent.
For 50/50 to be the "norm" on separation, it first has to be the norm in together families. Both parents need to make use of flexible working requests, part time hours, unpaid parental leave, taking annual leave to cover childcare in the summer holidays. Both parents need to take equal roles at home, not one parent "helping" the other. I am not referring to your case specifically Anita as obviously I know nothing about it other than what has been posted here, but thinking of cases that have been in the media such as that of Louis de Bernieres who spent a lot of time travelling away from home leaving his wife at home looking after the house and children, yet expected that when he and his wife split he should get 50/50 custody of them. I find that to be a ridiculous assertion, and I fail to see how removing children from their main carer 50% of the time is in their best interests, especially when those children might already be confused and upset at their parents' split.