What is likely to happen?

stbx is procceding with divorce though still awaiting initial notification so unsure what is going to happen so having to guess of likely scenario.

This is kinda long but wanted to give as much information as possible....so sorry

In respect of possible spousal maintenance, i have 3 children 9,7, and 6.
We are joint owners but very little equity in the home i guess approx £10 - £20k
I am due to start a new job which will earn approx £3k pm.
I expect to pay CM of £630 due to the fact i am in the process of applying for a variation (Other wise it would be around £730) due to contributing to 50% mortgage £120pm ( because rates are low and interest only this will go up!) and £342 for a second charge on home ( i pay 100% of this).
In addition i am apying in the region of additional £100 for sky tv, insurance etc.

In total a contribution of £1192 based on these figures.

I expect to move into rented accomodation soon close to childrens school to assist with my contact and if possible residence application which i believe will cost in the region of -
Rent - 900
CT - 145
Utilities - £100
Tv, Phone, BB - 50
Petrol - £200
Food - £400
Total approx £1800

This pretty much utilises all that i earn and would mean potentially trying to get lower rent to enable me to save for my childrens future.

MY stbx who has just literally given up a job in a nursery offering her hours to suit and close to home and school just to get leagl aid.I guess she has probably given up £7/ 800pm.
I can not for obvious reasons and will most likely need to self rep.

She is in addtion to the CM getting benefits though not sure how much and earnig £250pm (undeclared i guess) teaching privately.
Basically she has the ability to earn if she wants but chose the benefit route so not much i can do about that.

I recognise that i earn the greater amount and have the potential to as well i suppose, however i do have to factor that my future earning capacity my diminish due to a eye condition which currently effects my left renedering it pretty much useless as contacts and glasses do not help. There is the chance that the condition could also affect my right as well possibly needing a transplant...though i stress possible.

In consideration of the facts is there someone on this wonderful site that would be willing to put their neck on the line and predict if i would have to pay SM as well and thus have to reconsider my budget and where i am going to live?
i hope not but given SM is on a case by case basis i''m a little concerned i might have to at the same time.
Thanks for reading this loooooong question.

It looks far too tight for sm on the details you give. Up in the north, sm is pretty uncommon really. I believe it''s seen more often on the south of the country.

Thanks for your response, i hope so as it doesn''t make much sense if was forced to in the long term.
I couldn''t quite work out if this applied to every NRP earning more or those who earn a excessive amount more ie the rich and famous.