Sure, Carlos. The visa will remain valid as long as it is not abused. However, you'll be seeking a CR1 visa, not the obsolete/defuct K3 visa that became all but dead in 2010.
I recommend you file an I-130 to initiate the CR1 spouse visa process, not the K3. K3 visas are effectively obsolete, with only a handful issued globally in recent years.
Anyway, whether your spouse-to-be pursues CR1 or K3, her B tourist visa will remain valid until expiry date or until revoked by the consulate. In my case, my existing B visa was revoked by the issuing consulate soon before they issued my spouse visa.
