Will offer what we can from our experience etc. Hope it helps.
Was good that you sat down & did a little self analysis and got your "list" together. I think that helps keep focused on tackling things in a logical manner. That to me is real important as a lot of this stuff will try to drag you in an "emotional" direction and if you don't keep some logic in the process it can just run away with you.
1> Emotional demands
One of the big things in general about increased "numbers". It will remain a challenge to keep balance there even if everything was all warm & happy
But my instinct (nothing more) tells me that some of this emotional demand at the present may be "control issues". You kind of allude to that in another line about being accustomed to the "V" configuration - you being the center. I think you're going to have to practice "letting go". If your relationship with your hubby is good and solid, you have to TRUST ! Trust - and keep TALKING
Sounds like this is a new, but kind of expected bridge that you haven't crossed yet - so cross it TOGETHER. Trust that your love for each other will guide you safely to this new place.
2> "Space" issues
This is a biggie - especially for women, we feel, more than men. There's some stuff posted here addressing this. If you can't find it I'll try to help or elaborate if need be. I'm sure most of the girls here can address this better than me. But you HAVE to acknowledge this in a gentle manner and figure out a solution. If not, it can overshadow the other stuff. This is (potentially) the EASIEST to conquer (finances allowing) and other stuff deserves more attention.
3> Used to being the "hinge" - center of attention
Think there's a couple of possibilities here you'll have to soul search about.
First, maybe just the "ego" part - the being pretty much center of it all. It's been a wonderful thing but I'm assuming you knew from day one that that would not be guaranteed to last forever. Seems maybe that time has come. So now - ego is threatening to topple the whole tower. You don't want that ! (I hope) Give ego a kick and tell it to get back in it's proper place
It will fight - but YOU are in the driver's seat.
Maybe we have a little jealousy/insecurity surfacing ? You don't specifically mention whether your "lover" was M or F. If they are female then this isn't a concern probably - already crossed that bridge. But if not then this may be the first time that this nasty "competitive" monster has emerged. In either case, it pretty much comes down to the same thing.
That big ol "C" word again - COMMUNICATE !
Sit down and talk to your husband (and lover) and just explain it's new and you're feeling a bit threatened. It's normal and nothing to be ashamed of or keep bottled up inside. Talk it through. You'll likely discover that the "fear" is way out of proportion to the reality. Pretty standard stuff. Work it through. It help that connection with everyone !