It comes out of my benefits. Mine
Then you have good grounds to obtain it all back. And I suggest you apply to have them sort it out. Because your income is nothing to do with anything.
She didn't even discuss maintenance, just went straight to cms who have said it shouldn't be coming out of my money and csa were wrong to take his war disability pension into account. He's set up a standing order to pay but it's only because cms have listened to him. His ex won't talk to him, she just wants money. She's literally bled him dry
She is under no obligation to discuss it with either you or him, yes it's desirable but no she is not obliged to. If she's willing to pay the assesment fee and collection fees then that's all she needs to do.
They are not wrong to take the war pension into account,for the purposes of CM (and many other things) it is treated just the same as JSA and subject to the minimum benefits CM payment,this is what they do with it. The link I posted earlier confirms this is the case. So no nobody has told you that is was wrong for the Csa to do that.
If he has debt as a result of the relationship and has not retained the asset then he can apply for a variation as can he for contact related travel costs.
He is doing nothing other than paying the legally required amount towards maintaining his child/ren,life may be far less stressful if you stop being quite so hate filled about his obligations towards the children he had before you. Do not date or get In to relationships with people with kids if you are going to be so resentful about the legal obligations they have towards these children,that's just common sense.