There is no need to file for an annulment. If your foreign spouse obtain a valid divorce abroad, the divorce is recognized here.
The specific Family Code provision is Article 26, specifically the second paragraph. It states:
Art. 26. All marriages solemnized outside the Philippines, in accordance with the laws in force in the country where they were solemnized, and valid there as such, shall also be valid in this country, except those prohibited under Articles 35 (1), (4), (5) and (6), 3637 and 38. (17a)
Where a marriage between a Filipino citizen and a foreigner is validly celebrated and a divorce is thereafter validly obtained abroad by the alien spouse capacitating him or her to remarry, the Filipino spouse shall have capacity to remarry under Philippine law.