I actually worked as a schools inspector in the rural north-east of Thailand for several years. (In the province of Buriram for anyone who knows Thailand) So I do have expertise in his area.
The village GFs family will usually expect signs of wealth from the farang (foreigner) boyfriend. They wouldn't kill you, as you are a golden goose. Most Thais have very large debts, often hidden, and so if money is suddenly needed such as a hospital bill, your GF, or her family, or her cousins, neighbours, friends etc will be looking to the foreigner to help them out. And yes, Thai hospitals WILL turn off life support machines if there is no money coming.
Now try to say no.
What happens is the foreigner comes to live in a village, miles from anywhere, and soon gets bored as noone really speaks English, and there is nothing to do. So he drinks.....a lot. Other girls will launch themselves at him as he is loaded (in their eyes), or start nasty rumors about him seeing other girls/boys, trying to engineer a split.
Your village GF expects not to work, or you have to set her up in business. Beer bars, beauty salons, cafe/tea/coffee shop are popular, (and expensive to run), but the smaller the village, the smaller the chance of a profit. You will be expected to teach English
According to local news reports you can hire a hitman for $500, or less.
Your biggest cost is health insurance which gets very expensive as you age, or after you have made a claim. 30% increases are not unheard of. Over 65s are in many cases unable to get insurance at all. About half the long term expats retired to Thailand do not have health insurance, according to the consulate in Pattaya.
Like most countries, Thailand has pros and cons.