Without one you will need to prove what you had before in case of divorce. Otherwise everything that could have been acquired during the marriage would have to be split half half.
Idk about US rules but it sure helps a lot if you marry in Thailand. Bang rak (Amphoe in Bangkok) is famous for that.
After that the marriage just needs to be registered at you embassy. And later an entry into your home country is thousand times simpler (at least for all European counties) !
Edit: Switzerland is sure one of the best countries when it comes to simple government paths
It took me 2 weeks to get all papers and my wife needed a little longer. Then we went to bang rak at 07:00 ( they accept only a few couples per day!).
Add on: make a prenup!!!
I prepared it via email with Siam-legal and we went to the office in Bangkok the day before marring (prenup must be there or it’s not accepted by Thai law!)
Everybody without Thai passport does the arrival card. It’s just a way to know who enters.
And you will enter without visa. It’s call visa exemption which most countries are entitled to. Only a few passports need to go get a visa on arrival - not a single western country ;)
If you have informed yourself just a little then you know that the money must be in the bank long before extension. And obviously you will have to have a room the day you arrive.
And then: it’s hard to drop money before opening an account.
So there you go:
Rent
Account
Money
Extension
If you’ve prepared well, the first 3 are done on the first day and the last 90’days later. That’s what I did (although I opened the account on day 2 and the money arrived the next day 😉 )
Just make sure that the bank recognizes the money as foreign!!
So you either by an onward ticket right away or wait and see (and maybe need to stand in line twice).
At onwardtickets dot com you can buy one for 10-15 online within seconds.
Edit:
Concerning your retirement.
You need to get a bank account asap and put your 800k in (hopefully they will show as foreign transfer!)
I have Bangkok bank and kasikorn and I recommend kasikorn as 711 doesn’t allow scanning QR codes from others and Apple doesn’t accept Bangkok bank card as payment method in an Apple ID