Without you, I couldn't have done it.
Without you, I wouldn't have done it.
Is there any meaningful difference between those two above? In my humble opinion, the first one sounds as "I wasn't able to do it, and then you showed up before me." On the other hand, the second one sounds like "I didn't even attempt to give it a try until you showed up."
However, some of websites hiring native-Eng people, which give English translation services in my country, put the word 'would' for almost everywhere too often. The very reason I showed the examples above is that they translated a sentence (it meant the first example above in my own language) into the second one in English.
They clearly stated that their translation would be incorrect because their men are not professional, though. Anyway which is correct? Please teach me.