This is not correct. The applicant needs to clearly demonstrate strong ties to Thailand and that they will return. It doesn’t matter if they have a husband or a boyfriend, if the interviewer has any concern that the applicant may stay in the US, that’s where you get the no. When my wife (then girlfriend) applied, she provided them my details and ties to Thailand in addition to her own. It can be tough to meet their idea of qualified, but it is not predetermined and being a wife or a girlfriend of an American citizen is probably equally concerning when they weigh your circumstances.
Based on your description, it sounds like you may have been offered a fraudulently obtained visa. Call around to other gyms that are not potentially putting you at risk. Even if you do train there, if they get caught with other fraudulently obtained visas for their “students”, you could get flushed out with the others.
The first week I moved here, my girlfriend (now wife) took me on a minivan to a different city and on local busses in Bangkok to get around. Then, I found out how much the bts and taxis and flights and private cars cost, and we stopped using minivans and busses.
My wife was able to get a visa when she was my girlfriend, and unemployed (early 2019). The issue isn’t that you need this amount of land or that amount of money. The issue is that she needs to convince the person reviewing her application that she has sufficient ties to Thailand and will return. In my wife’s application, she demonstrated that I lived here long term and that we lived together as part of her case. My situation added to her situation, and she got approved.
There is no specific formula… just make the best case you can that she has ties to Thailand and is not at risk of staying if she visits.
I would strongly advise you not ask about working remotely on a retirement visa at the immigration office. Your options are to work under the radar (illegally) or get an LTR if you qualify. Find a reputable visa agent that can walk you through this and distance yourself from anyone trying to sell you a special solution or that tells you they have a contact or connection. There are a lot of scams and schemes that seem like they are legit, but are fraudulent.
You can be denied entry by an IO at anytime for any reason. If they suspect you are gaming the system, it is discretionary on their part, so what usually happens or what should happen may not happen for you. Best to get a visa more in line with your situation to avoid the gamble. One grumpy government worker can wreck the best of plans.
It is possible for a foreign spouse to file for a divorce against an American citizen in a court in the US. The laws vary from state to state, but your marriage abroad could result in a divorce proceeding back home. Probably a good idea to look in to that and make sure you don’t get caught off guard some day by a crafty lawyer.
Not true... many people have been denied entry for too many visa exempt entries or tourist visas in a short amount of time, and it is up to the IO to make this determination. Don't leave it to chance. The experience of being denied entry is unpleasant. Get a visa that is correct for your needs, and don't set yourself up for a bad time.