Mortal love?

This is based on everything I have ever seen around me and also some personal experience. It is infuriating when things are so very obvious (or should be) to everyone, yet they still repeat the same shit endlessly, we intelligent beings should be able to identify the problems of our nature and change something. But...
Most relationships either end up failing, or continue just: for the sake of continuing, 'fear' of popping the bad news about your dissatisfaction for the comfort of avoiding unpleasant conversations, fear of ending up alone.Yet, these would be a small price to pay for giving yourself a chance to change the part of your life that is burdening you.

The standard relationships go something like:

One notices the other, or they notice each other (target spotted before or after conversation). Everything starts to revolve around that person, they become the focus of your thoughts and feelings during any and every of your activities; so, probably your dreams, too. Let us call that person X. X is the one you genuinely feel happy thinking about, your serotonin is sky-high. You look forward to just any type of contact and a text message or a call mean the world. You picture X when things are bad at work and suddenly those problems seem diminished. Consciously or not, you feel satisfaction when others see you with X, because you feel proud of them. You're in awe, your face hurts from all the smiling, you listen to and soak up every word X says, even if it is not really your type of subject or field, you take interest in it, because you want to get to really know X. You bend and extend your interests for the sake of that. After all, if you choose to share your life with someone, you will share all kinds of things: the ones you are interested in sharing, and the ones that you are less excited to share, but that are included 'in the package'. You look at them with adoration and every hug, kiss leaves you thirsty for more. In intimacy you give things time because you never want the moment to end, cuddle, play, look into X's eyes because you desperately want to get right to the core of their being. All this, while feeling like you are the luckiest motherfucker and have had the honor to meet the most wonderful person on the face of the planet, and not only that, but they are all yours, and feel the very same way. What more could you ask for, if things are like this?

But most people do end up wanting more. Or, not 'more', really. Just that their appreciation for X lowers as they start taking things for granted, and they use the excuse that 'it can't always stay as it was in the beginning'.
The question is: why not? Do you remember how you used to look forward to meeting them every time? Especially if there happened to be distance in between and time apart, that should have been a painful lesson of what it's like to be without them. You felt like once you get your arms around X, you will never let them go, and would have done just ANYTHING to see them for 5 minutes. Just so that after a few months/years, you'll give them bored kiss or even forget to kiss you when meeting/ parting. The contrast is really painful, if you think about it.
You start looking around, the initial focus point faded and you think/ say 'mmm :>' when you see a stranger (on a screen, in real life, etc), and hardly react that way to X anymore...You start seeing other people as sex toys (because, c'mon, that's what all the attraction/ attention thing comes down to), but are hardly ever impressed by the partner that you were once THAT much astonished by, or even more (I am saying 'even more', because X raised your genuine interest and kept it alive as to make you fight for their proximity), no matter how much effort X puts into being/ staying just as attractive to you. Less attention, less appreciation, less genuine passionate, romantic, connection-creating sex. You'll have that area covered with the lame excuse of a robotic, purely physical sex (the kind that you'd do with those you say 'mmm :>' at). X will start hating making plans with your friends, because you will start to treat them indifferently in a social environment, no more the complicity, polite actions that once were, you know, when your 'toy' was new and you used to be proud of 'it'. Now you ignore them, exclude them, you even make observations that make them feel bad, in front of others. X will be depressed when thinking back at the time you were out and would have wanted them to be there, too. Actually, every situation contrasting between 'now' and 'then' will make them depressed. And more and more, each day.
Of course you can't and shouldn't be constantly with your tongues down each other's throats, 24/7...but it doesn't hurt to keep the essence of the way things started, in order to be...you know, happy. Otherwise, sharing your life is just a complication, so the damage is bigger than the benefit. Superficiality and indifference will probably eventually leave X wanting more and gravitate towards something they feel good about. And the ironic thing is, you will be the one who will miss them when you again will have a cold bed, just like in the first days when you missed them. Or, they will just settle, which will bring them to frustration and make you both miserable (a bit more on that here ).

Whether we want to or not, we feel. Why give ourselves just a taste of the best meal we have ever had, just to push it away and salivate at it from a distance, when we could enjoy just a bit of it every day? It is really not impossible as long as it feels worth the while and you want it.