desperately need advice for retain right of residence :

hi respected board members and guest,

well, i am from pakistan and i am married with EU member 1-05-2012. we married in cyprus.
we moved to UK january 2014..
since the first day we are living together for five years,
now our relationships is destroyed . we are on divorce/seperation level.
since 2014 we are in uk , we are living together and she is still working legally and taking treaty rights.there are no gaps..
my question are :
what kind of documents do i need to apply for Retain right of residence?
how long does home office took to decide my case?
in case of refusal do i have right of appeal?
how many percentage chances do i have to get ROR ?
does Brexit can effect my case ?
do i still in old law?
i got all her payslips,job letters,council tax letters,tv licence ,internet etc are on our names,
i am really too scared and depressed.

please help me in this matter,
it would be grateful.
have a good day and be happy...

No need for multiple posts - stick to this one.

Start here:
https://www.gov.uk/government/uploads/s ... _clean.pdf

If you have adequate supporting evidence and meet all requirements you have a high chance of success.
You may have appeal right if initially denied.

Brexit is 2 years or more away so don't worry about that for now.

Case may take 4 or 6 months or more to be decided.
Good luck.