First of all, according to your description, the reason why you are angry is because your boyfriend had a dream. Although he thinks during the day and dreams at night, he can't understand it simply. Because some scientists have explained that dreams are the expression of distorted human thinking, I think this explanation is more scientific. So since it is twisted, it is not what he really thinks, so you don't have to blame your boyfriend for dreaming.
Secondly, your boyfriend tells you that he has a dream, which shows that he trusts you unconditionally from the bottom of his heart and he has a clear conscience. You may even say that he lied to you, and a room full of little sisters are you, but I think this should be a white lie that he cares about your feelings in order to reduce misunderstanding. This is also a normal reaction of people.
In short, it is not easy for two people with different personalities to walk together, and it is inevitable that they will encounter obstacles in life. Learn to be tolerant, and you will find that life will be better.