...are just hurt—if it's as childish as I think it is—or if it's just a reminder of my very low place in their hierarchy.

I hesitate to bring this up because when I have needs or concerns they label me as difficult or needy. Is this part of a bigger trend I'm missing? Should I stop taking him places and avoid the potential conflicts? Should I do anything to address this or just continue to stay out of their business and go where I wish with my partner?

Treated With Outrage

I'm having a hard time reconciling these two statements, TWO: "This has by far been the best relationship I've ever had" and "...when I have needs or concerns they label me as difficult or needy." I suppose it's possible all your past relationships have been so bad that your best-relationship-ever bar is set low. But taking a partner's needs and concerns seriously is one of the hallmarks of a good relationship, to say nothing of a "best relationship ever."

That said...

I don't know you or how you are. It's entirely possible that when you share your needs and concerns you come across as—or actually are—needy and difficult. Our experience of interpersonal relationships, like our experience of anything else, is subjective. One person's reasonable "expression of needs/concern" is another person's "emotionally manipulative drama," TWO, and I would have to depose your boyfriend and his wife to make a determination and issue a ruling.

That said...

It's a really bad sign that your boyfriend's wife compared eating in a restaurant you visited with him to fucking a hole that was just fucked, i.e. "sloppy seconds." It has me wondering whether your boyfriend's wife is really into the poly thing at all. Some people are poly under duress (PUD), e.g. they agreed to open up a marriage or a relationship not because it's what they want, TWO, but because they were given an ultimatum: we're open/poly or we're over. In a PUD best-case scenario, TWO, the PUD partner comes around quickly on the open/poly thing, sees that their fears were overblown and that poly/open actually works for them too, and they wind up embracing openness/polyamory and aren't technically PUDs anymore. But most PUDs, in my experience, don't come around and will engage in small acts of sabotage to signal their unhappiness. They didn't want to be open/poly in the first place and are determined to prove that open/poly was a mistake and/or punish their ultimatum-issuing partner. And the most common form of PUD sabotage? Making their primary partner's secondary partner(s) feel uncomfortable and unwelcome.

That said...

As you (probably) know (but if you don't, you're about to find out) poly relationships have all kinds of (sometimes incredibly arbitrary but also incredibly important) rules. If one of their rules is, "My wife doesn't want to hear from or about my girlfriend," TWO, then you can't expect your restaurant recommendations to fall anything but flat. If she's comfortable with the poly thing on the condition that her husband's relationships with other women are separate and distinct from theirs—if she doesn't want to be your sister wife—then suggesting cute date night ideas for them is off the table. Being poly relationship means navigating rules (and sometimes asking to renegotiate those rules) and juggling multiple people's feelings, needs, and concerns. You have to show respect their rules, TWO, as their each other's primary partners. But your boyfriend and his wife have to show respect for you too. Secondary though you may be, your needs, concerns, feelings, etc., have to be taken into consideration.

Finally, TWO, you aren't your boyfriend's property and you're free to go at any time. If their rules make you feel disrespected, unvalued, too-low-on-the-hierarchical-poly-totem pole, etc., you should end it.