Love this thread. It's something I've thought about a lot.
There are of course two sides to every story and unfortunately I find that conflict can happen when you have multiple people in a relationship (hell, it happens enough in mono relationships!!).
Staight-out trash talking, I wouldn't tolerate. I also don't do it. For me, these things are not good -
) my girlfriend's secondaries badmouthing me to her
) my secondaries badmouthing my GF to me
) me badmouthing my GF's secondaries (to her)
) my GF badmouthing my secondaries (to me)
) either of us badmouthing each other TO our secondaries
BUT... sometimes stuff happens. Sometimes we DO behave selfishly and offend our partner's secondary. It doesn't mean name calling is ok. Communicating like adults is the only acceptable approach.
I don't actually believe that all parties need to get along. BUT - it makes poly easier when they do. Ideally, everyone's friendly, or at least civil. If my GF doesn't like my secondary, I do want her to tell me. If my secondary isn't keen on my GF, I'd want to know. But that's all I need to know. If there's a specific issue... tell me about it to fix it ... or leave me out of it and sort it out between the two of you.
Another thing we've learnt is to show a solid front.. and I wonder if your hubby is doing this? In the early days, my GF and I would conceal affection with each other in front of secondaries, to make our secondaries more comfortable. This seemed to create a pattern where perhaps they saw a way in, or didn't see the love between us. These days, we are very open with our affections and try to pick secondaries who make really good first impressions on each other... that seems to have helped to avoid trash talking.
As far as I know, nobody has ever told my GF that they don't like me... or that I'm a selfish bitch... hahaha... (lovely). But she's told secondaries in the past about our relationship issues... even relationship doubts... We've had long talks about a recent guy, because although she never seemed to say anything bad about me, I didn't feel she was giving him a true representation of our relationship. He once referred to me (in front of me) as her 'friend'... I live with her, raise her child with her and she calls me her wife... yet she saw no issue with his terminology. He would constantly text when we were together and instead of telling him the truth, that she was with me, etc, she'd say 'I have tons of work to do, I wish I could talk to you'... or worse, "I have to spend some time with Sparklepop, but you are in my thoughts". To me, that gives the other person the idea that the primary relationship isn't important and can give an opening to disrespectful behaviour and problems.
I think the best way to act is to show a solid front without blindly defending anyone. I don't think hubby needs to take your side (unless he believes you are in the right - in which case, he SHOULD defend you)... but I DO think he needs to say that badmouthing is off the cards. If hubby's GF is upset with you... he should tell her not to use that kind of language about you in front of him; but instead to talk to you directly, or come up with something constructive that he can talk to you about on her behalf. Hubby should also not complain about you to any girlfriends... it only fuels the fire.
Bottom line... no namecalling whatsoever... whether it's hubby's GF about you, you about her, or anything else. If hubby secretly feels that his GF has a point... he needs to speak up to you about it. If he doesn't, he needs to come to your defense.
Me: (30f) open poly
GF: (40f) My long-term, long-distance partner
Hubby (37m): GF's husband
Garcon (26m): GF's submissive/third partner
“Peace comes from within. Do not seek it without." ~ Buddha