They sound like swingers who want to keep their plaything to themselves with only their rules as acceptable. I don't think they really know what being polyamorous means. The fact that she so vulgarly asked if you want to suck her husband's cock -- when you simply asked to see them -- really shows that they are (or at least, she is) not thinking of you as a flesh-and-blood-and-heart-and-soul human being who might just want to get together and talk. She sees you as just someone to do her sexual bidding so she can get off.
What audacity and fucking nerve that you must be exclusive to them when they offer so little beside recreational sex on her terms only!
A girlfriend should be someone who does things with them, shares dreams and hopes with them, and has non-sexy times and well as sexy times. I wouldn't say yes to any exclusive arrangement with them unless I felt I was on level ground and/or could have other relationships. Do ask what they envision a girlfriend to be, exactly, and how they would like to see the future unfolding for all of you. I would think that if I've sucked someone's cock, and it's still not okay for me to have his email or phone number, or his dick inside me, then they've got some sexual and relationship hangups that do not sit well with me and I'm just being used like a whore. It's one thing to reclaim the word slut proudly, but if someone treats me with no respect and I feel like I'm viewed as their whore and sex toy, that's something I would never stand for.
I don't mean to be offensive by using those terms. They are not derogatory so I am not sure why it would bother you. . . . Forgive me, I am out of my depth. But I don't see how referring to polyamorous people as such or identifying their relationship in that way is wrong or should bother anyone.
I get why it bothered her. Because being treated decently is something that anyone deserves, whether in a poly or mono relationship. That's why SNeacail wrote, "Just because there are 3 people involved, doesn't mean any of the basic rules of communication don't apply nor that you need to accept certain behavior you wouldn't from any one else you were in a relationship with." Your asking if it's okay to put up with what they've handed you in a poly situation does sound as if you are not using your own common sense about how you deserve to be treated in
any kind of relationship. It also makes it seem like you think that poly allows for such gross mistreatment as you're getting. So, it could be frustrating to read again and again, "Is this acceptable in poly?" or "Is it okay to ask for this in poly?" when the problems you are dealing with are about how you want to be treated in relationships, in general.
It sounds like you know something feels wrong about this situation, but you are not trusting your gut intuition because you think polyamory might let some of those things slide (hence SNeacail's "Don't assume anything" comment). Poly is about love, respect, and honesty. The focus is not on sex, although of course it's an important element, in polyamory. If anything, poly requires ultra-vigilance in having respect and consideration for others. So, really, all you have to ask yourself is do you feel good about this arrangement and are you willing to accept the kind of treatment they give you?