I have made compromises for Ds to go private, but I feel it's nothing too far - and selling the family home is def too far!
All our holidays are haven / Butlins type affairs and we rent off a family member as I can't afford to buy. Our tenancy is secure though, I'm not sure I would feel differently if I was in general renting. Ds is an only child and all his dads maintenance goes towards the fees, so I literally pay for everything else myself.
It's not always easy but DS is in the right school for him, he has flourished there, and I'm hoping for a scholarship at the next stage. He will never know that there are sacrifices being made (though I do think he should know he is incredibly fortunate to goto a private school - as are all his friends) and I don't care what his outcome in terms of career is, so long as he is happy and has his education to fall back on.