I have many many foreign friends of various ages and nationalities that have been married to thai women, some friends once and some have remarried afew times,
After reading your post and giving it quite some thought,
If i was you,
I would either walk away or say no to these extra demands,
If people are already asking for these things then imagine down the line and my friends said the same.
They are testing you to see just how much advantage they can take of your generosity,