@Scratchclaw2017 - there is a legal position, and there is what is actually best for the children.
Legally - yes, you will get your 50/50 if you go to court.
As to what is best for the children - that is different story. And it is not about YOUR ability to parent, or what you currently do. I think currently you are doing really well - as in you are spending a lot of time with the children, you are present in their lives in a really meaningful way. And, MOST IMPORTANTLY - their lives are not disrupted by logistics of moving around.
So often divorced ex-spouses make this fight about 50/50 about themselves - and assuming they need to fight for the time or they are not full parents. (leaving the financial implication here for now). However - children don't perceive their parent's roles in days of the week numbers. They judge and remember their parent's involvement by the quality of the relationship.
So - my advice here - is try to separate your anger over the affair, etc. And don't feel like you need to prove or defend your father's role by fighting on the days.
Personally - I'd first establish your new home. Make sure your kids are involved in making their rooms in your new place - truly theirs. Get them to chose things for the rooms, etc. Than start with the routine as is.
And as the time progresses - you can see if some changes can be gradually introduced, and if the kids are receptive.
An abrupt change - where they, say - have to move out of the home they have known all their lives and live in a new home IS quite a dramatic change. And while for you it would be a WIN - over your ex, and a fair win as she had the affair, and you had to move out, and you didn't cause it. BUT in the end of the day - it's your children who are having to go through the change that will make their lives harder.
So - maybe, if you can - let things evolve? Put them first, hard as it is...
On the child maintenance point.... Setting aside the time arrangements - how are the costs divided now - clothing, uniform, school lunches, holiday cover, activities? Food is the only cost that depends on the nights kids spend in a house - everything else does not depend on it.
If you are contributing your fair share to the children costs - then I agree, there should not be any maintenance on top of that. But if you are saying - ex is s top earner, so I should not be paying for their clothes, etc. - then I don't think it's really defensible.
In the end of the day - if you push for 50/50 and get it - you'll have to cover 50% of their costs anyway. So - use that as a guidance...
Not sure this helps, or answers your question.