On curious question: "NOW, just out of curiosity, my question: if A and B, after renouncing their Filipino citizenship, became a citizen of a state that recognize same sex marriage. Later, A and B contracted such marriage. As per civil registry records of that state, although A and B are both men, they are considered married to each other. Their family relationship and property regime are governed by the law of that state. Subsequently, A and B wants to re-acquire Filipino citizenship?
What is the effect of their subsequent re-acquisition of Filipino citizenship insofar as the validity of their previous valid same sex marriage?"
Law should rule upon their marriage. In our case, Family Code does not simply recognize it.
(In case of dual citizenship, the foreign law, I presumed, has clothed rights inherent to their marriage such as property regime.)