Poly might not be right for you. I'm glad to hear you are thinking of that. If you find yourself in need of much more than you are getting and you want someone in your life that spends more time with you, doing things you both love together, reaching some life goals and is also there for you for the long haul, then perhaps monogamous bf's are a better bet for now or maybe always.
I don't think that one has to stay poly all their lives, for some it isn't an option and they always will have many loving partners that they are devoted to and have sex with, but for some its a passing part of the journey of their life and changes in time and circumstance. Sometimes it changes back again. I can totally see poly as an option until such time as a monogamous relationship is needed and sought after. Both options are valid. Deciding what is right for you is what is important.
I think you could still love and spend time with your bf and your metamours and still be in his life but end the partnership aspect. He sounds very busy with several people, I can imagine that the time factor would be a big one and maybe its better to be loving friends instead.
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