The purpose of spinning plates is not so that you develop strong feelings toward a particular woman. Heck, implicit in plate theory is the reality that the more women you meet and date the more likely you'll meet a quality woman you want to stick around and even make into a monogamous LTR if that is what you want.
The purpose of plate spinning is that if you focus on only one girl at a time, you are MUCH more likely to beta-backslide, approach her with a scarcity mindset, put her on a pedestal, and do all those unattractive things that drive women away.
If you are spinning 2-3-4 plates you are much less likely to come of as desperate and needy.
You will be much less likely to put up with her BS when she gets out of line.
Spinning plates helps you keep many of your attractive qualities at the forefront, keeps you in frame in the relationship, and so on.
Now, none of that means if you decide that you'd like to make one of your plates exclusive that you maintain a quality alpha frame. Not at all. That work still lies ahead of you and might even be harder for some guys once they've stopped all the spinning (I've done it myself, unfortunately).
All that said, I find when I'm dating 2-3 women at a time, I am in fact less needy, more outcome independent, pass sh1t tests more easily, attract other women in turn, and so on.
More criticism of your post coming from other board members in 3...2...1...