If you have filed an I-129F petition for your fiancée and you visit your fiancée abroad and decide you can’t wait any longer and you get married before your I-129F petition (the K-1 visa petition) is approved, it will significantly change your immigration process. The K-1 visa is specifically designed for foreign national fiancées who intend to enter the U.S. to marry their U.S. citizen petitioner within 90 days of arrival. However, once you are married, your spouse is no longer eligible for a K-1/fiancée visa, because the engagement-based visa no longer applies.
Instead, after the marriage, you would need to pursue a spousal visa, which falls under the IR-1 or CR-1 visa categories. This process requires filing a new petition (Form I-130, Petition for Alien Relative) and starting a different track entirely. Your existing I-129F petition would essentially be voided or denied since the basis of eligibility (being engaged and intending to marry in the U.S.) no longer applies. This will lead to devastating delays. Your process will not go faster because you are now married. You will lose the time you have already been in the process. You will lose the fees that you have already paid. You will need to start over and pay new fees.
In short, if you decide to marry before the I-129F is approved, be prepared to switch to the spousal visa process, which will take longer to complete. It’s crucial to plan carefully and consult with an immigration attorney, especially if your plans change mid-process. Making an informed decision can help you avoid complications or unnecessary delays in bringing your spouse to the United States.