This is a big topic. When there are no court orders in place you and your ex are both technically equal in terms of who the children live with. However the parent who spends less time with the children (or none at all if contact is being prevented) is the one obliged to pay Child Maintenance by law. This is worked out as a percentage of your gross income with a percentage reduction for each child after the first. Make sure you pay this by standing order to your ex's account, in her name, with a reference saying "Child Maintenance" so you can't be accused of not paying it in future. These things do happen, with an ex claiming that payment was for something else (eg mortgage payments) and not CM and you can then get billed for it again by the CMS. So it's always important to have proof it has been paid. It is calculated annually so payments may go up or down. The ideal situation is both parents sharing the care equally and both working, with a 50/50 schedule for the children and if this is ordered (or agreed) then there is no Child Maintenance to pay. Even then the CMS has to approve this and decide whether or not it actually is shared care or not. Even when there are no court orders and neither has "residency" as such, the CMS assume that the parent receiving the Child benefits is the main parent with care and can still make an assessment for CM. Some Dads have to appeal this decision. Child benefits can only be claimed by one parent and not be split between you. It's the way that system works.

If you're recently separated or divorced you may find you are paying all kinds of things informally if you've moved out - the mortgage and bills for the former family home etc. Be careful to have it recorded and designated which payments are for what. So rather than just pay the mortgage, set up CM payments under one standing order and a separate standing order for any other financial contributions you're making in the short term - to make up the total of any financial contributions you're making. Always keep CM separate.

Ideally don't move out until you have a Child Arrangements order in place - either by consent or via the courts.

Check out the Child Maintenance Calculator on the forum and get support and advice from other Dads on the Dads with Kids forum, who have been through the system.