I have a question in mind for some time now. Though I tried... to find an answer reading lot of stuff here for some time now, I still haven't felt that I have found a clear answer. So, I think you are the best person to ask this.
I wonder whether you ever had to face this kind of issue in your life because you always date with new girls. But I know there was a period, you were much more a relationship-focused kind of guy as you have mentioned it in this, Self-Expansion and Growth in Relationships article. So you may have better idea about this. My question is,
When someone is in a long-term relationship with a girl and when the time start to pass and sex life is fading away regularly, how someone can introduce novelty to their sex life... ?
I mean, when you are dating new girls and having sex with them regularly, this won't be an issue. Because she is new to you, and you are new to her too. So both of you have excitement, attraction, novelty, it is always there.
But, when you are in a long-term relationship how can you maintain novelty in your sexual life.. ? When it fades away, what can you do.. ?