The House – managing models when others are involved

I understand creating a model is only about “me”, my thoughts, feelings, etc., yet there are others involved in the model, and where do they go, what to do with them?
Ideally, I would like to move forward so that I can live in a safe, secure, comfortable, affordable, organized, serene home (I would like to get help with making that intentional model).
My husband wants to build a house, I have no desire to build a house much of it due to my husband’s tendency toward dreaming, talking and not taking action.
Our house is more than a century old, in disrepair and we will have to move out, fix it or something – found more problems this morning.
I would prefer to move into an already built house. Husband wants to work with an architect and build his own original design. He has been speaking about this for 10 years, and has suggested building a Quonset hut, a silo, a house made out of shipping containers, and he has oriented the house on the property in every imaginable direction except diagonal. Every time we talk – every time – he changes which way he thinks the new house should face. He keeps changing his mind, putting ideas out there, dreaming. I am action-oriented and doing something (at least I used to be). I have had to learn to “pump the brakes”/slow down/not act when he says things and try to discern which things are serious and which are conceptual and idea generation.
I have many thoughts about building a custom house, including: this will be disruptive, expensive, frustrating; I will be the person who has to manage the whole thing, because my husband is conflict-avoidance, “too busy”, non-confrontive, complains and bitches but takes no correction actions. I will wind up having to take responsibility for “his” project.
I have looked to find evidence that not all design/build house projects are the things mentioned above, yet I have not met many fans of the process (plenty of people who like the end result, but not the process). I also have evidence from having to remodel a house post-hurricane, working with contractors, etc. I did not enjoy the stupidity, disruption and frustration.
My husband says that I get tensed up when he talks about it, (and it is likely that I do), so he doesn’t talk about it. When I talk to him about moving into an already built house, he shuts down, and says “Fine, forget it, I guess I’m just stupid.” or “Never mind, it’s a stupid idea.” Ugh. Then I think, “OMG, I married an 8 year old.” (yes, I understand my model is operating perfectly: my “T” creates more “A” where I have to be the “adult” – pay the bills, laundry, HH chores, clean the yard – while he watches cartoons, builds his music playlists, and draws because he has to relax from his stress-filled work, and of course I don’t want to bother him or have to tell him to do things that I think he should know to be doing – that’s straight from my manual 😉 ).
We are now at a point where we need to make a decision on moving out of here, building a house, etc. I don’t want to dump on his dream, but then I don’t want to wind up having to give up my time and sanity for something that he probably won’t have any interest in, beyond design. There are so many other thoughts too: I am also worried about money, how will we afford it, if we spend money on this we won’t be able to do other things, I am not liking this city anymore, and I probably will want to move out within a few years into a slower paced community…
My model looks like this right now:
C: House
T: My husband just keeps see-sawing back and forth, coming up with some crazy ideas and not committing to any, so when something goes wrong during the project, it will somehow be ME who has to fucking clear it up. I don’t want to do this, I think I will be doing it “alone” and it’s not “MY thing – it’s HIS thing.”
F: Resistant
A: Tense up, can’t communicate, won’t discuss, don’t make progress on this house or another house, looking at other places, no repairs to this house,
R: We haven’t made any progress, and our current house situation is getting worse, going on 10 years now, we haven’t updated or fixed our current house.

Thank you.