Hi

Link to CMS online calculator: https://www.cmoptions.org/en/calculator/

Firstly, the child maintenance is calculated on how many children he has with his ex (in this case one son of 8 years old) using your partner’s gross income (after any pension deductions, and if he is in receipt of any of some very specific state benefits listed in the calculator). There are potential deductions depending on the number of times he has them stay overnight with him in a year (there are different bands for this deduction) and how many other minor children, if any, live in his household (if he lives with you, this would be either children he has with you, or if any you have from a previous relationship that live with you both).

To be very clear - it is not currently calculated on how much his ex / stepson’s mother earns (neither is your salary part of the calculation even if you live together and/or are married).

If he gets a pay rise of *any* amount, he should rerun the calculation just to check that he is paying the correct amount. Other than salary increase, the only other way maintenance could increase is if he reduces the amount of overnight contact he has with his son, or if he has no
other minor children living with him (if they were deducted previously but have since ceased to live with him / are now adults).

This is separate to any financial settlement regarding child maintenance on divorce (although you can ask for it to be recalculated along cms lines after 12 months from the consent order), and totally separate from any spousal maintenance (what Americans would call alimony). The stepson’s mother could take him to the CMS or to court if she believes he is underpaying / hiding pay rises etc, but you should be able to remedy this very quickly provided he has been paying what the CMS calculator states.

If in doubt, get some family law advice or go to CAB.

Hope that helps!

It sounds to me that the UK uses some form of the Income Shares Model for establishing CS (Child Support). If the UK system works similarly to the US system... nothing causes an increase in support unless one of the other Bio-Parent initiates a CS review. Generally, even if a CS review is requested and ordered, CS will remain fairly stable unless there is a significant change in either joint Bio-Parent income or parenting time. Additional children for either Bio-Parent, at least in the us, does not tend to change CS as having more children is the choice of the parent and the prior relationship children should not be impacted by that parent's choice. Cost of living, increased transportation costs, etc, etc, etc..... also usually does not impact CS once established without a significant change in circumstance.

One thing with the Income Shares model (in the US each State usually has an on-line DS calculator that can be used to estimate CS levels) that I found fascinating is that even if one Bio-Parent's income remains flat of goes down significantly CS can actually go up if the other BP's income increases significantly. In our case the NCP's income remained flat for decades while my wife's (the CP in or blended family situation) when up regularly and significantly over the years. During that time the NCP added three more also out-of-wedlock children by two more womb donors and when a CS review was requested his CS level went up. It took him a few cycles to learn this when he would attempt to get his CS lowered. Every time he tried to get it lowered... it went up even though his income remained flat and his spawn count increased.

Generally in the US the income of a Bi0-Parent's partner has little to no impact and in most cases cannot be considered in calculation of CS. There are some rare situations where a partner's income can be included in a CS assessment but those are fairly rare and generally fall under the discretion of the court.

In our case since as the idiot in the black wizard robe with the stupid Fischer-Price wooden child's toy hammer stated "since StepDad makes a significant income, Bio-Dad should not be punished by having to overly contribute to an artificial standard of living for the child." my income was considered though minimally. The Judge then ordered an income reduction credit be applied the SpermIdiot's income in order to reduce his CS obligation. The max credit that can be ordered in the County where our CO was issued is a $1000/mo reduction in income which only reduced his CS obligation by $50/mo. That held for the duration of our 16+ year Custody/Visitation/Support order whether the joint household income of my wife and I was at the initial level when the CS order was issued or 15X that much a decade or more later.

I would recommend that you do some research on the CS calculation model that is used in your local and play with the on-line CS calculator (I assume that there is one) to see how income, parenting time, and added non-joint children will likely impact the CS landscape in your situation.

If this research leaves you with any major questions ... I suggest that you contact a lawyer to get some advice.

Good luck.