Short answer. Not on the strength of the absence alone. Article 349 of the Revised Penal Code protects you only once a court has declared the absent spouse presumptively dead by a judgment rendered in the proper proceedings. Without that judgment, a second marriage is bigamy no matter how many years have passed.
What the law says
any person who shall contract a second or subsequent marriage before the former marriage has been legally dissolved, or before the absent spouse has been declared presumptively dead by means of a judgment rendered in the proper proceedings
Revised Penal Code, Article 349 — Bigamy: Second Marriage. Read the full provision →
What the article actually requires
Bigamy is committed by any person who shall contract a second or subsequent marriage before the former marriage has been legally dissolved, or before the absent spouse has been declared presumptively dead by means of a judgment rendered in the proper proceedings. The escape route is there in the text, but look at how narrow it is. It is not "before the spouse has been absent for years". It is not "before the family has given up hope". It is a judgment, rendered in a proceeding, by a court. Years of silence, a barangay certification, an unanswered phone, relatives who all say he is surely dead — none of that is a judgment, and none of it will stand between you and a charge.
The Family Code sets the waiting period
The court judgment referred to is the declaration of presumptive death under the Family Code. Article 41 of that Code allows the present spouse to remarry where the absent spouse has been missing for four consecutive years and the present spouse has a well-founded belief that the absentee is dead. The period drops to two years where the disappearance was in circumstances of danger of death — a sinking, a plane lost, a soldier missing in action, a disaster. The well-founded belief is a real requirement, not a formality: it means you actually searched, and can say where, when and whom you asked. A petition filed with no history of looking is the usual reason these cases fail.
What the declaration does and does not do
The declaration does not end your first marriage. It lets you contract a second one, and it makes that second marriage valid — but the Family Code also provides that the subsequent marriage is automatically terminated if the absent spouse reappears and an affidavit of reappearance is recorded. Property and the status of children are then sorted out under Articles 43 and 44 of the Family Code. So the protection is real, and it is also conditional. What you should not do is marry first and petition afterwards. The article fixes the crime at the moment the second marriage is contracted, so a declaration obtained later does not undo a bigamy that was already complete.
The penalty, and the practical route
Bigamy carries prision mayor, which is a serious custodial penalty — this is not a technical or victimless charge, and a complaint can come from the returning spouse, the new spouse, or a relative of either. Anyone who knowingly took part may also be exposed. The safer course is the slow one: gather what you have on the disappearance and on your search for the absentee, and file the petition for a declaration of presumptive death before, not after, you set a wedding date. Where the first marriage was itself defective, a different route may be open, since Article 349 also excuses a second marriage where the first has been legally dissolved. Which route fits your facts is worth taking advice on before you commit to either.