I have been to a lot of these SEA countries and spent between and a month to 6 weeks in each and didnt experience this really, I spent a month in Cambodia and didnt see or hear anything of it there. Thaliand I saw the odd old dude with a young woman which were less than half their age but then again I avoided Pattaya and Phuket as it's not my seen and I was back packing
I have been to a lot of these SEA countries and spent between and a month to 6 weeks in each and didnt experience this really, I spent a month in Cambodia and didnt see or hear anything of it there. Thaliand I saw the odd old dude with a young woman which were less than half their age but then again I avoided Pattaya and Phuket as it's not my seen and I was back packing