(A fair-weather friend is easy to find, a real friend is hard to find)
(literally: friend to eat together, i.e. someone who is your friend as long as there is food on the table, like a "drinking buddy" in the West)
On a similar note, weddings between Thai and Farang are not closed with "...in good times and in bad, in sickness and in health..." but "...as long as the (Farang's) money lasts...".
Better than having the money stolen by some greedy Thai boy, or losing value in Europe (inflation rate higher than interest).