NADM - I know we disagree about the NMW job thing, but YOU wouldn't have to pay your DP's maintenance if he took whatever NMW job was available.
Yes, they use a portion of your DD's CTC's, but a) CTC is part of your HOUSEHOLD income, not paid individually but based on your household income, and if your DP was employed you probably wouldn't get any anyway, and b) As you have another DC resident in your household to support (your DD), your DP's maintenance receives a reduction to allow for that.
So taking the TC's into account, that you wouldn't be getting if he was employed FT, unless you earn less than £15k pa before tax & NI, is offset by the reduction in payable maintenance to allow for the fact that there is another DC in your household that needs to be supported, your DD.
Give with one hand, take with the other!!
I still think the OP's DH's Ex is taking the piss if he is paying £20-£48 a week. If he is paying more than that, then his Ex is royally taking the piss moaning about losing anything on top of that until he finds a proper job.
However, IMO, you don't have the luxury of trying to build your own business at the expense of supporting your DC's, unless it has been AGREED with the Ex partner (the RP) that maintenance payments will drop during that period.
It's called being a responsible parent - you ensure that if you wish to build your own business, you can still afford to support your DC's to the tune of what you would be paying in maintenance in a FT NMW job.
If you can't pay the £48 a week for two DC's that you would be paying if you were working in a FT NMW job, then you are being irresponsible and shirking your responsibilities to your DC's by following your own wishes and dreams at the expense of supporting your own DC's.
Which isn't responsible parenting IMO and IME.
I DO have issues with this, because I am at the other end of that situation, and get just £12.50 a week in maintenance from my DD's father because he is 'building his own business', when if he took a NMW job, he would be paying nearly £37 a week for one DC!
So because he is following HIS dream, I am getting £25 a week less than I should be, and would be if he stood up to his responsibilities, and did what I have had to do at times since having our DD, and work a shitty NMW job to support our DD.
I don't class that as good or responsible parenting - I class it as selfishness, and childishly following your own dreams without thinking about how that will affect your DC's.
And as for the thought that if they were together they would both have to tighten their belts - if I was still with my DD's father, no way would I have agreed to him following a pipe dream of trying to start his own business instead of taking A job, ANY job, even NMW when he has a DC to support.
So why should I accept that just because we are no longer together?
If I as the RP have had to work shitty NMW jobs to support my DD, why the hell can't he?!