I'm sorry you struggle.
I don't knwo if this could help you but this is how it sounds to me....
I love everyone involved and need advice on ways to remedy this crazy situation
Could behave in loving ways to all your partners then -- not participate in "less then honest" and "lies of omission." Those things aren't loving behavior (to me.)
I don't like how things can't be more open with her. I don't like that it makes it so I'm having an affair with her husband and she with mine. And of course we are all betraying her because we can't tell her we all know.
If that is your bottom line?
You could start with YOU being open and honest with your loved ones. 4 players have to do it, but it could start with YOU.
You could tell them each solo (DH, BF, and Meta Wife) that you are no longer will to lie/pretend. Then tell them again in a quad with all there so there's not triangulation he/she said stuff.
- You want to be together in an honest and open way.
- She wants to be together in secretive ways.
- What does BF want?
- What does DH want?
Where is each person's "willing" and "able? "
- What blocks people's WILLING?
- What blocks their ABLE?
- If some need to grow skills/confidence to BECOME able (meta wife? others?) then how does the group plan to handle that?
- How can the blocks be removed?
Talk it out and sort yourselves out.
If this talk means the whole things folds, it folds then. It is just NOT compatible with all the wants/needs to exist in a healthy way. If all 4 are not willing and able it will not fly. (Or at least very WILLING to be in polyship together and ALSO willing to work on their ABLE.)
You want to share something more real and authentic? Could go for it then.
take the risk it could become that.
It certainly won't arrive or appear by magic -- you have to help make it so with your partners.
Could start by you aligning your own behavior to match what you say you want more of -- be more "open and honest" rather than you holding yourself back from fear of having to deal with her reaction. If you know she is "feeling attacked" or "pressured" when various people bring it up verbally -- how about over email? Written long hand? Could she be willing to talk it out that way? Couples Skype? Something else? Since you want the WHAT (to have the conversation,) you could let her choose the HOW to have it or the WHEN to have it. Negotiate on some points so it moves along and she gets some say somewhere. That could help relieve some "pressure" since she's being talked with
rather than talked at.
In the meanwhile, could take a break on the swinging "play" -- that just adds to the complications. If she asks why? Tell her. "I don't want to swing play as a group until we talk things out first. When could we all sit down and talk? Friday work for you? (or whatever date)"
People could bring lists of talking points. Knock 1 or 2 off for each person's. Or 15 min each. Then get pizza after an hour. Everyone got a little something, nobody got overwhelmed. Knock some more off next week. It doesn't have to be broken down in one go.
You could help move it forward, rather than help keep it in the stuck.