To be fair, if this is someone's first experience in Poly, they may well not realize what their expectations are, or what the reality will be. It's a completely different animal from what they may be used to, and I know I went through my own growing pains in my relationship as well.
Ignorance of how something works, and trying to muddle your way through it is hard as hell, for everyone involved (been there, done that), but it's certainly not malicious. The fact that the OP is here talking and asking questions is a good sign.
Mono. Divorced, two kids (DanceGirl, 14; and PokéGirl, 11), two cats, one house, many projects.
My partner. Poly. In relationships with me, Xena, and Noa.
Poly. In relationships with Chops and Noa, and dating others.
Married, Poly. In relationships with Chops and Xena (individually).
Blog thread: A Mono's Journey Into Poly-Land (or, "Aw hell, there's no road map?!")
Slightly more polished blog with a mono/poly focus: From Baltic to Boardwalk