Except shit happens and toes get stepped on. My partner and metamour mean well - no doubt about it, but yes, toes get stepped on. And it's much less effective to expect my partner to handle it if he doesn't understand why my toes were stepped on. Usually, in that case, things get miscommunicated. Better that she and I talk between ourselves - P doesn't even need to get involved, although we usually keep him in the loop.
P's new GF? I don't know her as well, and she hasn't done much more than small talk with me. No big deal, but it makes communication in that case a little more difficult, and I would probably get P in the loop a bit earlier. I'd still say something, though.
In a perfect world, sure, there'd be few incompatibilities, but we're all imperfect people who get hormonal, who have pop-up issues that need addressing, or who really don't understand how one action could possibly affect the other person (and P doesn't always grok what would bug me and why). It happens, and it's not caused by P's inability to manage his relationships or a need to "babysit" him.
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 a relationship with Chops. Dating others.
Married, Poly. In a relationship with Chops.
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