In the name of your wife / significant other you can invest in any business you wish.
In your own name as a foreigner, you can not.
Even under the new One Person Cooperation (OPC) rules, you are still bound by the limitations of the Foreign Investment Negative List (FINL).
One example from that list is that foreign investment in any retail business with a paid up capital below 25 million peso is inhibited.
So that pretty much prevents foreigners from owning any business where you intend to sell anything (products or services) to individuals.
The full FINL is found here .