I have been thinking about this poly style for a little while now. I have told J a number of times that I could see myself choosing to be monogamous at points throughout my life for various reasons, generally tied to big life transitions: moving, a new job, if we ever decided to have kids, a friend or family member dying, etc. I have thought about how if I genuinely didn't have any interest in having other partners, how this style would probably work for me. I would still understand the poly perspective, and J's need for other relationships and partners.
Interestingly enough, I think we have both moved in waves with this style. There have been a couple of points in the past year and a half where we have each taken a break from dating and seeing other partners. I know I am in one right now. I just don't really have an interest. I feel emotionally drained and scarred, and I need time to heal. That being said, seeing more casual partners sounds good still... I guess I'm not totally in a monogamous space. It's the need to be out of emotionally-heavy, drama-filled space.
Thinking about it long-term, I have asked myself the question: Could I be monogamous? Do I want to be monogamous? Sometimes, when I am feeling really low, I think, well, yeah. It just seems easier. But immediately, my gut says NO. I could never give up the freedom, choice, and ability to be with women, to have other men in my life, and to engage in the activities that J and I do together. I also know that monogamy isn't easier in theory. It's just the way I, and almost everyone else, was socialized, and so I know the rules of the monogamy game much more intuitively and innately than the rules of the poly game. All relationships take work, and all relationships have highs and lows, regardless of their structure.
I am fascinated by couples who make this combo work long-term. It seems like it takes extremely self-aware individuals who aren't afraid to ask for what they need and who are giving enough to satisfy their partner's needs.