Pre-nup agreement

Well you must realize theres a certain amount of flexibility with the rule of law in the Phils and often any agreement is only worth the paper its written on.
So with that in mind leave your investments/money etc overseas and draw a income from there. Its a case of not putting all your eggs in one basket.
However much of this situation depends on who rather than how much. By that I mean if you fear a money grab is  on the table then you have the wrong women, pure and simple. if you go at it with a negative mind set in this regard you may well get what you fear.
What you need to do is take your time get to know folks on the ground, do some net working like the Philos do, make local friends. Hook up with expats on the ground in your chosen area. In short assimilate as much as you can/able do in the time you have given yourself.