Thoughts on poly/mono relationships
So, I'm new here, and I'm new to polyamory, hooooray!
I identify as a lesbian (with the occasional interest in men) and I've been dating my poly partner for about 6 months now. So far everything has been pretty amazing in our relationship, but I have been thinking a lot about how functional a poly/mono relationship is?
My partner and her bf have been together for 12 years, so I have no doubts about their stability in terms of their own relationship, but they decided to open it up to additional partners as long as they're of the same sex... so she can date me because I have a vag. and he can date dudes if he wants but I don't think he's into that at all. So basically, they're operating on a one partner being poly, while the other is monogamous dynamic.
What I'm wondering is, and hopefully you experienced poly people out there may have some insights, how well does this sort of arrangement hold up in the long term? Now I know these sorts of answers are completely subject to people's personalities/needs/interests/boundaries, etc, i guess I'm just always concerned about causing issues with their relationship.
I haven't really seen anything manifested as of yet in terms of side effects to my girlfriend being in another relationship, but I do sort of get the vibe that her bf sometimes feels left out. You see, they were never affectionate when I first began being friends with my gf (before anything sexual even was considered), but I do see him get all nostalgic and cuddly when we're all hanging out and she's being intimate with me. I assume this is a natural reaction, i sort of see it as a "hey what about me" kinda thing, which is totally ok, I'm just wondering what role I play in making sure he's getting the attention he needs. I guess my immediate thoughts are that it's my gf's business to make sure her relationships are gelling, but I want to be a conscientious participant as well, as we all have a stake in this.
Is the general rule to just leave other relationships to the other people and meddle as little as often? My gf has been confiding in me that her bf has been a little more insistent that she try and make time for vacations with him (which would be all well and good except that she has other life factors really holding her back from traveling, work/research, and I feel like he's making these requests somewhat as a kinda, "oh you don't want to travel with me now, oh I see". I've taken to the opinion that I should be a champion for their relationship, support what makes her happy, that sort of thing, but when you can see that one partner's requests/boundaries are ill-conceived and maybe stemming from slightly... "selfish" desires or insecurities, do I owe it more to my gf to be practical about the matter and support her inclination to not take vacations right now, since her obligations would make it a poor decision, or should I be more laid back and support the vacations?
I guess the core question is really: what role does a 3rd play in supporting the other relationship/to what extent? oh, and if anyone has triad success stories, please, do share!
I hope that wasn't too wordy....