Two quickies, the first on the inter-cultural issue of money.
As suggested, do explain to your Thai lady the limits of your income and also your unavoidable committments such as tax and other dependents. It could be complex.
Also tell her if you dare that you have some savings... but it will hard to persuade her that these should not immediately be spent on rice land, a house for Mama etc.
I suspect that Thais do not generally leave money lying in bank accounts and would immediately spend a windfall.
A farang is a windfall, a lottery win even! What's the point of money of you don't spend it!
Secondly, to widen the original post's request for books which focuses primarily on inter-cultural areas, what other books can anyone recommend on Thai culture itself.
If I have a favourite, it's Silkworm Books', "Letters from Thailand" by Botan, a pseudonym for its female Thai author.
If Thailand is run by the Chinese/Thai elite, understanding this community explains many of the contradictions of 'Thai culture'. It is in fact not one but several cultures.
This novel tells the story of a poor Chinese immigrant through the letters he sends back to his mother in China and it taught me more about the role and integration of the Chinese than anything I've read. It's an engaging story and I'd recommend it highly.
So what other books are there?
Andrew Hicks
PS And thanks for some nice comments above about mine!