I don’t think that there’s one view of monogamy that is shared by everyone in the poly community. I do think that one of the core tenets of monogamy is the idea of the “one and only” and that you are supposed to be getting all of your romantic, sexual, and physical needs met by one partner. There is a pervasive idea that if one person isn’t doing those things, they aren’t the right person for you. Perhaps some people feel their partner does those things. I don’t feel that one partner CAN do all of those things for me, because I have varied needs and desires. Nor do I want to put that pressure on one person to be my everything.