Christian purity is not something you are born with. In fact, the Scriptures teach us that every human was born with a sin nature (Psalm 51:5). Thus, we do not sin and become sinful. Rather, we sin because we are sinful.
A foundation is the most important part of any building. Likewise, when it comes to God building your future marriage, the foundation is one of the most important parts.
While there will be some very clear signs when God is truly revealing your future husband to you, there will also be elements to this experience that will feel odd.