Child Maintenance payments while living together (separated)?

[HappyDay5]

Hi, I hope this is just a quickie for anyone reading. I'm just (tomorrow morning) about to return to the marital home with my STBXH while we divorce. I left him due to financial abuse.

It was a long drawn out battle which is not quite over but essentially, the mortgage is cheaper than any rent in the area and the house is big enough for us to avoid each other. The rental I was in has been sold and there is only 1 other suitable property available and they won't let me rent due to the affordability criteria (even with a guarantor) as they don't take tax credits or CM into account.

Once the divorce is final we'll go with whatever is ordered regarding the house/living situation. He'll no doubt stay at his girlfriend's while I'm around for the coming months and I'll probably make myself scarce when he has his child contact time. We have two children together, 8 and 6. He works full time in a fairly well paid job and I work 4 days a week for a charity, topped up with tax credits. We separated last July and he's been paying £400 per month until today. He hasn't transferred any money and hasn't responded to the text I sent earlier chasing it up. I suspected this would happen as he doesn't want me to move back in and has been hiding out for the last few weeks - ignoring all correspondence from my solicitor notifying him of my intention to move back in.

I originally offered to pay all costs associated with the house if he were to move out and the kids and I continue to live there. Alternatively, I offered to pay for half of everything if he stayed. I'll continue to pay for all additional costs associated with the kids while they're with me just as I always have.

Although it seems like he's giving me £400 just for me to give him back £630 (half of house running costs) every month, I'm still fairly certain this is how it should go so we ensure our finances are completely separate. I hope this will all be sorted in the next 6-8 months and ideally to keep everything we already had in place on track so I'm still financially independent - albeit under the same roof. He'll at least be over £200 a month better off if we can set this up. I think that seems fair?

Does anyone have any experience of this? The agreement we have was set up by child maintenance options and he pays (almost the correct amount) to me himself rather than direct pay.

I've brought the kids for a sleepover with friends tonight as my old house is now vacant and the marital home is upside down with bin bags and expedit units. I plan on the move happening in the morning but now feel like the residual financial control is creeping up on me again and I've come too far this year to let that happen again.

Am I justified in asking for this arrangement? Wine poured and ready for advice...