You can only file a fiancée visa if you are:
A US citizen
Not yet married
Not going to marry until your fiancée comes to the US
After your fiancée is admitted to the US, you must marry within 90 days and apply for their green card. If you are not yet a US citizen, you are already married, or you plan to marry the person before they come to the United States, your only option is to file an I-130 spouse petition after your marriage.