I am good with numbers so will try and summarise this:-
Total house value:- £221k (20+60+141)
You put in :- £20k (c9% of house value)
She put in:- £60k (c27% of house value)
Mortgage:- £141k (c64% of house value)
You pay the mortgage (although it is in her name? As it comes out of her account.)
You pay some bills directly.
You pay £300 towards other bills that have a value that you don't know and she won't tell you.
You get the benefit of living in the house.
But at sale - despite investing 9% and paying the mortgage off another 64% (so 73% altogether) you only get 25%.
Ok - there are lots of ways that this could be done fairly but the methodology is basically this:-
As she owns 75% of the house and you own 25% this is how it should be done to be fair:-
You pay all bills.
You pay £125 of mortgage plus 75% of market rent on house
She pays £375 of mortgage and gets 75% of market rent on house
How does the rent on the house compare to your mortgage.
Whatever else you do you need to get all the bills put in your name to stop all this whining. I can't imagine she is paying that much (if anything at all) on top of your £300 so all this "I can't afford to retire" is just to make you feel bad.
Personally I would start looking at whether you can buy her out (it sounds like you have equity so you shouldn't be - effectively - renting when you can afford to buy) or if not, selling the house and buying another one that is yours.