What should I disclose during my visa interview as a US citizen expat in Thailand?

Hello Everyone,

I have a question about my situation. I am a US citizen and am not working in Thailand. I have a fiancé (we are getting married next year in the US) who is teaching English here. I worked as an Engineer in the US, saved up money before coming, and am, in fact, purely a tourist. I am spending my time taking photographs, exploring the country, and planning my future when I get back to the US. I have no source of income. My fiancé’s salary and my savings support our lives here.

Currently we are on a two-week trip to Cambodia. I am attempting to get a SETV from Phnom Penh, but it appears that many are “VOID WITHOUT PREJUDICE” at this embassy, and they don’t do interviews. I supplied all required documents and am crossing my fingers. This situation is in motion and can’t be helped. This will be my 4th SETV. The others were obtained in the US, Penang, and Vientiane. We have been in Thailand since mid-September 2018 (6 months).

My question is: how much information can/should I divulge if I am granted an interview (or for future applications)? If I explain the entire situation with my fiancé, will that help convince them that I am not working? Or should I say that I am traveling and leave my fiancé out of it altogether? She has a Non-Immigrant B and a Work Permit.

Or should I be using a different Visa? I am not retired, am not working, am not married. Any advice is appreciated. Thank you!