fiancé; fiancée
Refers to the person one is engaged to marry. Gender-neutral in Japanese; context or additional words clarify gender when needed.
彼は私の婚約者です。
He is my fiancé.
婚約者と一緒に結婚式の準備をしています。
I am preparing for the wedding with my fiancé(e).
He became my fiancé last year.
I introduced my fiancée to my parents.
I heard my friend got a fiancé.