I need help understanding my partner?

My busy partner whom is starting his own business, I think we’re a great couple and I make sure to support his goals and help him achieve them which he appreciates and loves, but I’ve recently disobeyed him and acted on my own self interest, and he saids it’s worst than cheating whenever I don’t listen to him, he said he wants the best for me so Nothing bad happens to me, but today he said “if you become a burden for my goals, I will have to let you go” and hearing that makes me feel very unsure, I told him I’ve done wrong and I didn’t mean to not listen to him, it’s my fault and he said “I do all of this so you can be successful and okay both of us” so I told him let’s fix it together, he made it clear he doesn’t ever want to leave me, he wants to marry me and have a family with me but why is it that when I don’t listen to him, he gets really angry? But keep in mind he’s always supported me and loved me and listen to me but whenever I’d disobey him, and do wrong, he’d get really angry but we are okay now, I just want to know why in views of other man, if my man is very starting a big company, but gets angry at me when I make a wrong mistake that could harm me, he gets really mad why is it? Does it mean he really cares then?
I need help understanding my partner?
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