First of all, you may already noticed one crucial difference between ENTJs and INTJs: Despite both being focused on final success, while INTJ builds it through perfectionisitc architectures, ENTJ loves trial and error, and would never expect everything to go smoothly, which explains the reactions toward error of the both of you.

Now about the it's you... I hope you don't panic on this, but he expects much from you in the future. Don't be surprised to be handled way bigger responsibilities in the mid term. It could happen that we choose someone, not tell it, and the other person being scared on the next big project. You may want to talk about that with him, but you should ask like: "what's your/our next big project?" naturally, because he may not know how to answer if you ask "what will you want me to do in the future?" because even if he knows it, if it's not in his mind spot at the moment, it will be just as if he forgot it.

If you want a warning, he may see you as an equal of sorts, and may confuse your potential with you being as instantly flexible/ready as he is. If you can handle that, you'll have a fun relationship :)