Can my ex go back to court again for maintenance?

4 years ago my ex and signed up to a Consent Order. In summary dividing assets 50:50, and me agreeing to pay CM and SM.

Prior to this we at a child care arrangements hearing we agreed to share the childcare equally - it is literally 50:50. Over a 2 week cycle the children are with me 7 nights, and my ex 7 nights.

Before getting to court my ex put a claim into the CMS for maintenance, but at the time mislead CMO claiming she had greater parental responsibility and they therefore opened a case and calculated a payment giving me a discount for the nights the children are with me. At the time I wasnt aware that when childcare is shared equally there is no CM liability, and therefore agreed to the consent order as I was under the impression that was correct. Having reviewed the case extensively the CMS have concluded childcare is shared equally and that therefore I have no CM liability. The order only lasted for a year, at which point the nil rate assessment overruled the court order.

I was aware my ex was co-habiting for some time (since separation), but she always denied it, until just over 6 months ago when I discovered she and her partner had bought thier house together over a year ago. There is a provision in the financial arrangements order for SM to cease if my ex co habits for 6 months or more, and ive therefore ceased paying her. I have the official land registry title deeds naming both my ex and her partner, her partner was named in the divorce application and they are clearly in a relationship with pictures of them together on holiday etc all over facebook. I have screen shots etc She did once admit in a text her partner was living with her, but now once again denies it, and has produced a "rental agreement" between her partner and his friend where he claims to rent a room.

My ex clearly isnt short of money, but despite this Ive said I will consider a family based arrangement but have asked her for a full financial disclosure, as I simply do not believe she needs the support she claims (6 holidays this year already and extensive work done on her new property), and yet I struggle with the day-to-day costs - certainly no luxuries like holidays etc. Shes refusing to do a full financial disclosure.

The financial arrangements order also has a section 28(1)a,b bar in the SM section.

My ex is now threatening to go back to court, she has already attended a MIAM session.

If this does end up back at court is it possible the I would again be liable for CM and/or SM ? ....Ive been told by the CMS that the CMS is the authority on CM, and that the courts are unlikely to overrule any decision they make. And I think I have pretty good evidence of cohabitation, and if the court agrees the evidence is sufficient, is there any way she can make a further application for SM - especially given the section 28(1) bar ?

It is very difficult to advise you on the wording of an order which I have not seen.

In general terms, it is always possible to apply to vary an order for SM on the grounds of changed circumstances under s31 of the Matrimonial Causes Act 1973.

This order may be for a term expiring on a fixed date, or it may be open ended and terminate on the occurrence of a specified event, for
example the re-marrage or death of the recipient.

Where an order is made for a fixed term, it is possible for the recipient to apply for the extension of the term. However an order
under s 28 may prohibit this, with the result that the SM ends on the date specified in the order.

Even if an SM order has a fixed date, there is nothing to stop the payer applying for a variation or even a discharge before the fixed date on other grounds - for example change of circumstances, or
the re-marriage or death of the recipient, either of which may end
the order.

What s 28 does is to prevent the recipient applying for an extension of the fixed term.

If, as seems to be the case with you, the SM ends on the occurrence of certain events, and that event occurs ( in my case it was the death of my ex wife ) you can just stop paying.
When she died, I didn't need to apply for a discharge, because the order itself specified that the order would end on her death. I just
enjoyed doing what I had waited 28 years to do, and handed in
a letter to the bank cancelling the standing order.

So if, for argument's sake, your ex is cohabiting, you can just stop paying the SM ( not the CM ). She will probably argue they are
not cohabiting and then it's for the Court to decide where the truth lies. If the Court finds against you, there will be a bill for arrears and probably costs.

But cohabitation of the mother does not end child maintenance.
Your liability is calculated by reference to a statutory formula.

LMM