Being a mixed couple (Dutch and Lankan), and caretakers for my wife's younger brother and sister, we might be able to offer some advice.
There is really only one general DON'T: Never ever sleep in the same house as the girl before it has really come to a marriage, or sometimes an engagement. Virginity is 'sacred' in most parts Lankan culture, and it does not matter whether you have shared a bed or not; the simple fact that you were in the same house has made her 'very much suspected' and her family's reputation might be at risk afterwards ('daughter is a slut') etc. etc
When she lives abroad there is (contrary to in a SL village) no problem with the two of you being in one room without a chaperon, but that's daytime only...
All the best,
<Erik> & [Sandya]