Quitting in the hardest part means you paid for the pain and skipped the payoff.

The hardest stretch is usually the last one before something gives, which is a cruel design and a consistent one. Leaving at that point means you did the difficult part and stopped just short of what it was for. Stopping for a good reason is not the same as stopping because it hurts, though, and only you can tell which one is happening.

When you want out, set a small distance rather than deciding forever. One more week, one more session, then look again. Make the call rested, not in the middle of the worst part.