As a straight guy, I have a seriously difficult time understanding how most straight couples work

Many of them adhere to certain fixed gender roles to the extent that not much of their relationships seem authentic. I(20M) am lucky in that I’m seeing someone where these sort of things don’t really matter, but I think we’re more of the exception than the rule on this sort of thing. I don’t oppose how most straight couples work since they all seem to be alright with it, but I just struggle to understand why gender roles tend to be so important to most straight men and women. It’s so much easier to be in a relationship where all that shit doesn’t matter.