K. First of all, I would say these things in front of your husband if he and I were having a discussion. I am answering this as I would any post, as it's how I talk. I am not changing anything just because I am your girlfriend.
I realize that your husband might not want to know what I think, but the fact of the matter is you have written this in a post, so I feel it is up for grabs. If there is something that comes up because of that then I will assume he will tell me. So, here goes.
Yeah, don't assume he'll tell you. He's not the best at talking to people until he knows them really well. Mostly I just get asked why he doesn't talk. And I have to reply with, "Don't get him started. He doesn't stop."
You seem to be having trouble expressing all this in times of heightened emotional intensity. I'm writing all this as a question in the hopes that I understand what is going on for you. I am hoping you will feel compelled to let us know if this is how you are feeling, and perhaps feel like you would like to expand on each point and add others.
You feel you are not being consulted or respected in terms of the speed this is going.
You feel like the delicateness of the situation has not been respected/considered in terms of you.
You are not feeling safe, secure and feel somewhat threatened by the situation.
Your insecurity about being a third wheel and not good enough is being triggered.
All of the above is making you feel out of control, and that is not comfortable for you.
Does any of this ring true? Would you change something, add something?
Yes, I feel out of control. There are a lot of unknowns. I'm a bit of a control freak with my life. I like to know what's going to happen and how I'm going to respond to things ahead of time, and in this situation I can't possibly know that. Yes, I am insecure, always have been. I've always had a bit of a feeling that I'm not good enough. I know that this is my own stuff. I really wish it would just go away.
I want to feel like I'm "fun." Yet again, it's something that I have to work on myself. No one else can make me feel "fun," and like I'm good enough. That has to come from me.
Nerdist and I have this kind of miscommunication almost daily. It can be learned from so that you can move on. It sucks, but in my experience, it's all a part of it. It doesn't help that everything else is going on, because moving on from it seems to go faster when there is nothing major going on. Which is why working on the other shit is helpful!
I barely know your hubby, you barely know mine, and we have known each other a year. It's a different type of knowing when we become a part of someone's everyday lives. It's not a casual thing. Metamours have a deeper relationship than just friends. I'm sure your hubby doesn't know her other boyfriend that well either, enough to want to be around him every day. To me, knowing someone enough to be in their everyday lives is being able to talk about the hard shit with each other without feeling like you are going to be judged and told to be dumped. Why would you want to invest in her that much before taking time to get to know her, and more importantly, how she is with hubby and your kids?
I probably know her other boyfriend better than he does. And he's nowhere near being a part of our daily lives! Although he is pleasant enough to be around, you don't get to know someone overnight. It takes time.
I'm ok with taking that time. I just want the flexibility to be able to say that I need a breather. There aren't many people that I talk about the hard shit with. It's another one of those things that I think makes me look weak. I'm so much about putting on a strong, confident front (which probably doesn't fool anyone).
None of us feel like that yet, in your whole constellation. I don't know how you are with my hubby, my boy, or my boyfriend, and we have hung out a lot. Why should you just shrug it off and believe that you will think she is the best thing ever because her boyfriends have said so? Why would you want to hang out with her all the time, or be okay with hubby being with her all the time? You and your husband don't hang out with me that much. In fact, the whole time your husband has been home, we have barely talked. Why? because I respect your primary relationship enough to give you time while he is around.
I'd love to have you and your family hang out with us more. Next time he's back, he'll be back for a lot longer, and there will be that time to hang out and have everyone get to know each other better.
Although I'll warn you now that the two of you will butt heads on a whole bunch of topics, but as long as you don't mind the debate, it's all good.

I just might move myself elsewhere if it gets too heated. My husband does love a good debate, and I am a poor opponent because I take it all personally. lol