I don't know if I agree with this entirely. I think it could be partially true, and part of being in a long-term relationship is always being able to keep things interesting for you and your partner. But I still feel that spark when my DH is at his most predictable--when we're at an event and someone says or does something and I just know exactly what my DH will be thinking in response to that. And I raise my eyes to meet his glance across the room and he knows I know what he's thinking. I don't think that is a 'pseudo-intimacy' if I can feel so drawn to him because I know him so well. Of course, there are times I expect him to do something I don't appreciate (like forget to do something I asked, for the third time), and that's predictability that is not a turn-on except for weirdos, but I don't think it's possible to make a sweeping generalization about familiarity being the enemy of desire. Maybe my general love of orderliness has taken over my entire body, though. And also, my DH has a ton of enthusiasm and passion for learning, and his job, and his projects, and when we do get a chance to actually talk we often have new things to tell each other.
Passion and eroticism require distance, not sameness. The security generated by closeness can cause our mate to feel more like a sibling rather than a lover. Eroticism is about the ongoing expression of desire for our mate. It requires individual sovereignty where I take responsibility for my own desire and arousal, not abdicating my responsibility by placing that burden on my mate. Itís refusing to believe I know my mate and instead choosing to see them as a deep mystery that I could spend 100 years trying to uncover only to still be surprised. Itís not my mate that has to change, for passion to occur I have to change how I see my mate and be honest with myself about who I am