I don't want to be dumping/venting/crying about issues with my boyfriend, but when issues do arise, he insists I can be as emotional about them as I want and that he'll be there for me etc. I feel like he isn't supposed to be taking on my issues and dealing with them, I should be maturely dealing with them as best I can on my own.

He needs or wants to know how you think and feel about things. He wants to be needed by you. If you don't need him, he is kind of redundant and superfluous. He needs to be needed. He wants you to complain more, because the act of complaining shows your weaknesses. And he wants to save you from your weaknesses.

Have you heard of the damsel-in-distress trope? It's used in almost every story written for boys, because guys like being needed by a pretty, attractive girl. This trope works marvelously. Intelligent, humble girls play dumb to attract the guys, because they know that men need to be needed. Boys might be intellectually aware that the girlfriends they keep are far more wiser, intelligent, cunning, and so on, but rarely do they know how much girlfriends pretend to be stupid, in order to keep the boyfriend.

There are several quotes that say that the difference between a man and a boy is that a man produces more than he consumes. Usually those quotes say that a woman is a woman who can find that kind of man. And your guy wants you to need him, so he can let you consume some of his, even if it merely consists of you being a bit less stoic, so he can be your rock to lean on.

I don't know what kind of man you have. He might want you to develop some co-dependency to go with his narcissism. Or he is a good, alpha male, who just wants you to need him slightly more.