I didn't read your post.
I'm glad I didn't.
But-I think my perspective may help you-because I'm the one who fell in love with a second person in our dynamic and you are right-the change WAS HELL for Maca.
It's not unreasonable to ask someone to give you more time and more support (which could happen to mean less time/support for another partner) when you have a need.
I have been in that boat as well-throw poly out the window for a second:
If I have a major health crisis-I need MORE time and attention.
But if my child is having a major crisis-they need more time and attention. our loved ones have to work within the bounds of defining where a NEED exists in terms of how they divvy out their time and support.
There were times in our transition when Maca NEEDED more of my time and support and that meant GG got less.
There was a time when GG needed more of my time and support-and that meant Maca got less.
Likewise-there was a time when I needed a LOT more time and support-due to having several MAJOR surgeries in one year with severe physical limitations for a whole year. There were almost no "dates" or "romantic times" for either of them. AT ALL. Not with me-not with anyone else. Because they were struggling to manage the household, me, the kids etc.
But-its important to learn to communicate a need without it being aimed at the detriment of another person.
Instead of "I need you to see her less because I'm currently having a major mental health issue (anxiety/panic attacks)"
it's more stable, healthy and functional to say
"I need more support from you (in the form of xyz time/call/contact) while I work to resolve this mental health issue I am struggling with."
If they choose to give you the support-either way-it's likely to result in less for their other partner.
HOWEVER-it's a clearly defined statement of YOUR OWN RESPONSIBILITY for YOURSELF without placing the onus of blame on the third party.
Does that make sense?
Feelings come up and with change it's not uncommon to have too much of an emotion to handle.
With the additional stressor of a wedding etc-it's not really surprising it was all too much to handle.
The key (for future reference) is in how you lay the platform for addressing your needs.
There is NOTHING WRONG with having a need and asking for help getting it met.
But-this requires us to
A) understanding that even if they previously said otherwise, a person can ALWAYS choose to refuse to support us.
B) our needs are our own responsibility. No other person "makes us" feel or "causes" our issues.
C) it is ultimately up to us to resolve our issues in order to manage relationships with other people & sometimes the way to make that work seems more difficult-because the "easy" path of demanding our way-isn't fair to someone else.
In this case-it's important for you to realize that if your needs take away from another person (your metamour) then a thank you may be in order for their patience in dealing with their loss on account of your need.
I find that when I let a metamour know "hey-I know it's a nightmare-but I have this issue going on.." they are usually willing to be supportive and helpful too. Whereas-if I tell my partner they need to back off with the metamour-it blows up in all of our faces AND
it doesn't actually resolve the issue anyway.
"Love As Thou Wilt"