AFAIK the important difference is the assets brought into the marriage.
If I have 20 million baht in assets, and the Thai I marry has none, that 20 million is still mine when we divorce. It's only assets accumulated during the marriage which are split 50:50.
There's child maintenance, fair enough. I don't know if there is alimony.
I do know palimony doesn't exist, because defacto relationships are not recognised here.