It's quite an endeavor, and it's even more intense depending on your social surroundings. By the time I identified as non-monogamous I had already been in a number of monogamish associations, so it wasn't as huge for me as it would be for someone who has always lived a traditional life.
I would focus my energy on examining what makes an association healthy, and worry less about how many people you are dating. This is true for all relationship types (including monogamy).
People fear and reject things that they don't understand, and this is doubly true when they live inside a traditional system that explicitly rejects everything outside of it.
There are plenty of reasons to stay monogamous, and fear of how your fellows treat you can be one of them. However, when we make decisions based on what we are afraid of, instead of what we love, we make shit decisions.