I think what you said about mastery is true for everyone, especially in intimate relationships. Ultimately, everyone will want a relationship where you know each other so well that nothing has to be said. I think here Fe just takes the practical route and does not expect everyone to read minds. That's just what it is -- just spelling things out and consciously looking at it together to see what it is. Fi has 'rules' too -- but they are not called 'rules' because they are not apparent. Fi seems pretty ok with not understanding other people's 'rules', respecting them as part of who they are. This is natural among Fi-users.
However, when you try to go across the Fi-Fe border, things get confusing for both sides. Fi-users feel like suddenly so much expectation is placed on them to act a certain way, and Fe-users have emotional explosions blow up in their face without warning. Of course, when two people desire a perfect relationship, this will slowly adjust itself as both people will try to accommodate to each other naturally, by learning more about each other and bend towards each other, achieving a natural compromise (which is not really a 'compromise', because the two people are motivated by their desire to fulfill each other) I think it's important not to place value judgment on the each other's way of doing things. I don't think it's fair to totally expect one partner to adjust, so Fe has to learn how to deal with less clarity, and Fi has to learn how to deal with more clarity. Just because something is visible doesn't mean it's cheap, and just because something is invisible doesn't mean it's selfish.
With two healthy individuals, what you described would naturally happen. However, no one is completely healthy, and people unintentionally do things that are selfish and hurtful all the time. I think when Fe feels restricting and Fi feels selfish, it's a sign that something is wrong that that much conflict was created in the first place. From my experience in my relationship, this usually happens when there is real life stress involved, and we are not 'at our best'.
I've experienced this!When something then goes to a point where you go: 'Do not do that!', it is a Te warning as to your coming close to changing the core or demanding a change in the core. It however does not mean the Fi-user doesn't see your point/isnt capable of seeing your point as to why you would wanna go that way. They usually will be open to a conversation about how to reach the goal (Te) using alternative routes that do not disturb Fi. Decisions as to whether or not Fi needs an internal review to accommodate the goal are entirely made by the Fi-user and the process often leads to brooding alone. It requires time, introspection and will often happen without you realizing, until you come across the change by accident, or they make it a point to inform you that *this* now has changed. Often they are more than willing to elaborate as to how that change came about when asked about it (after the facts, during they are still struggling with internal conflicts and opposing views!), but this does not often come up, so it rarely happens.
I just have a feeling that a lot of the so-called 'rules' are there for a reason. For example, I do have a moral code that I follow, which is I will treat others like how I wish them to treat me. I will try my best to restrain myself from doing hurtful things, even when I am angry or not feeling well, because I know it hurts when other people "take it out" on me. Sometimes when I am upset about something my INFP did and I try to explain to him why I was hurt, I feel like he thinks that my feelings are 'unreasonable'. That is until the same thing happens to him, and he realizes that, yes, it hurts, and that causes him to change his behaviors, so this 'external rule' becomes his 'personal rule' as well. To me, it just seems like a shortcut to just respect and accept how someone wants something a certain way without having to wait to experience it yourself.
I don't know if it makes sense, but a lot of the time, I think these 'Fe rules' are just a collection of other people's 'personal values' made apparent and are not necessarily evil.
Wow, this is looong.