I am in the same situation as you OP. But not living in UK means that there is nothing I can claim to bump up. Stbx moved out and rents a 2 bedroom flat, when the dc go to him, ds sleep with stbx and dd has the single room.
But, we are also wanting to keep hold of the house and try to keep things as similar as possible for the dc. I have always done the finances, and still do... so we are still paying bills as before, but now there is the additional flat rental. Yes, things are tight and I had to increase my salary (I am self employed but things are very up and down there too), just to get by with food and household stuff for the month. We have to pay school fees x 2 so usually I try to do it yearly, but just not possible now, so I have lost a good chunk in discount now...
In fact, I just had this discussion with dc at the weekend. Cannot afford any extras at all now....ds was having a hissy fit as he wanted his hair cut at the salon he usually goes to, said no and off to barber which is less than quarter of price. Dd has eye on new clothes for new season, have had to say no as well. She just wants, doesn't need
. But its what they are used to as before there was that little extra do to those things. No take aways or eating out now either, I sat this weekend doing meal plans.
So, yes its been difficult, and I think it still will be to come. I will try everything to try keep the house though, its the one thing that I feel so strongly about, to keep some normality for the dc, as they have been crushed by the separation.
But OP, even though things are tight, mentally for me I know its the right thing. Its been 3 months now. I know the time is going to come soon when we discuss the actual divorce...but just a step at a time is how I am coping at the moment. I know that financially, is the biggest reason why this didn't happen sooner.... but will cross each hurdle as it comes.