Having helped a few Thai widows over the years, there are frequently problems.
One husband died unexpectedly and his fears that his wife would, at some later date, upon his demise most likely donate most of her money to the local wat and monks came true,
Another husband set up a Will requiring the executors to make regular monthly payments to the wife for a period of 4 years after which she could have the rest as a lump sum, hoping that the family predators would have gone away.. The family however had another idea. They found their own lawyer, advised there was no will, and the deceased had no family, and the wife/widow walked away with everything. (As I understand it, she lost most of it to the family in a very short space of time)
Does the OP not have a work related pension?. In most cases wives, and more often than not, partners, can receive a pension of around 50%, sometimes reduced where there is an age difference of more than 10 years