A woman has a 469-bullet-point list of what a man must be.
A man has a 2-bullet-point list of what a woman must be: young and beautiful.
She is much easier to replace than you are. The chances are very high that you will be in another emotionally-satisfying relationship before she is.
It's a truism - out here, in the outlaw lands outside the mainstream that consists of twisted and fucked-up thought and emotions and what are laughingly called relationships - that he who cares the least in a relationship, has the power in the relationship. I'm thinking that this is an inadequate and inaccurate statement.
If you don't care about the relationship, then why are you even in it? From that you can see that it's bullshit. Unless you're in a strict fuck-buddy situation then not-caring is not-relevant. If you truly didn't give a shit then it'd just be a one-night-stand rather than a relationship.
Down this path is where jerks and assholes are bred. They so insulate themselves, because that's what they "learned", that they don't care about much. Including the girl. Which is why you have to wonder how they managed to get the relationship at all, it means so little to them.
Now, if you fear the least in the relationship - about losing the relationship - then you have power. If you don't fear driving her away, if you don't fear dumping her, if you don't fear being alone-ish until you can get another decent relationship together - then you have power.
This is where you become loving, caring, fun - and very firm in your boundaries and the limits of what you will tolerate. Call this "the caring jerk", spoken of endearingly by women.
Or perhaps something else entirely, something a step or three further.