Well, as stated above if you're the white dude from the West and in a long-term relationship with a cute Thai guy, you're going to be expected to be the bread winner. Wouldn't exactly expect them to start pitching in for rent or the grocery bill any time.
However, that hardly means they're all money grubbing lowlifes as you imply. It's not like they incessently bitch and moan for you to buy them a car or build them a house or anything remotely like that. From my experience, many of them are totally happy to live a modest life in a rented house, eat standard market food, et al.
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