It's a tough call, I have my gripes like everyone else but can put up with the BS as being based at Heathrow on whatever fleet suits my family circumstances and I live close by. Saying that I jacked in two previous careers to get here, both seen as a safe(ish) option with pension etc at the end so I know where you're coming from.
If I was single and didnt have a family I'd have a different perspective.
Try going part time and do something else on the side?
Edited to add: in no way should you feel guilty about considering leaving. It's just a job, if its not working looking for other options is exactly what you should be doing.