Wow... This is the first LDR question that has truly stumped me. You actually have strong reasons to stay where you are...
I'm in a similar shared custody arrangement with my two girls (50-50). Their dad and I both loved them very much and would never dream of separating them from the other parent. It does cause issues because things happen and you want to move... But neither of us have.
I don't think it's a good idea to take the kids away from either parent. They have to come first. While I don't think that parents should stay in an unhappy marriage for the sake of the kids, I do believe that parents should do everything possible to keep both parents active in the kids lives.
The good news here is that you're both in the same situation and can empathize with what one another is going through... That can actually bring you closer together.
When you say under 12 - exactly how far under 12 are we talking about? They will eventually go to college and move out on their own, but until then, I don't see many options.
Here's my brain dump of the possibilities:
- Keep going just like you are - part time relationship seeing each other when you can.
- Break it off because you'll be waiting for years to be together and we all crave companionship and physical contact. It's hard to wait for someone indefinitely.
- Try to get one of your spouses to move to the other state.
If the kids are old enough, maybe work the custody a little differently so that you can do the two household thing that you mentioned. I wouldn't try to move the kids back and forth between states until they're older - and even then, they may hate it.
This is just a tough situation and you're going to have to make some hard decisions. My advice is to make those decisions sooner rather than dragging this out over years wondering what to do.
Listen to your heart. Regardless of what anyone else thinks you should do or tells you to do. Follow your heart.
The only moment we ever have on this earth is this one - right now. Are you experiencing this moment in a way that brings you joy? That is the question that we should all ask ourselves, every moment of every day.
We like to say that with every situation, you have two choices - accept it (truly accept it for what it is) or change it (do something about it). Anything else will just bring you misery and sadness.