I have an opportunity to join a polyfidelitous triad, but I have some concerns

So I've been talking to a couple that has offered a very luxurious lifestyle, and they fit the bill in almost every way for what I've always wanted. They have been together for around 10 years, and initially they mentioned "triad & polyfidelitous" but it's also very clear as of talking (7 days) that one is a lot more interested then the other, or at least reaching out at all... of course on top this knowing that they have such a strong foundation already, I would sleep alone majority/all the time.

Only you can make the call here - do the pros outweigh the cons? Is this a situation that sounds fun enough to make up for any frustrations you'd have to put up with, or are there too many red flags for your liking? 

It's okay for you ask for more clarification of expectations. Lay out for this person the specifics of what you want, and ask if they are willing and able to provide what you want. Let them know what your dealbreakers are, and ask if they can assure you that none of those are part of the plan. Where there are discrepancies, talk about compromise and be proactive in problem-solving.

It's okay to hold fast to your requirements and boundaries. It's okay to be flexible and compromise on some things, too! But be sure that you're being clear-eyed and honest with yourself, not brushing aside concerns because you want it all to work out or assume your future self will just be able to repress certain desires or disappointments. Don't do that to future you!