I've always been in the same situation Cat - I'm sure if I tried, I could afford to keep it at full livery. But the cost of that in Surrey - which would be my closest "countryside" is just insanely expensive. I can't justify having a horse and then only seeing it twice a week (on weekend). My work is too long hours to do anything before or after work.
But for years now I've shared and that seemed to work relatively well. I've always been lucky enough to find horses that were primarily mind only to ride - the owners had babies (

) or just no time or interest anymore, but didn't want to sell their horses either. So I could do pretty much whatever I liked in terms of showing / competing etc.
Apart from the last two I've had that were complete and utter insane nutters - so much for "school masters"

more like "suicidal, lets see if we can seriously injure or kill our new sharer".