The metaphor of the church being the 'bride' of Christ is one of those metaphors that can require an extra shot of faith to be totally comfortable with. Especially if you are a dude. But listen to this: God chose you. And the metaphor of the bride is one of the ways this truth is illustrated.

In the middle east, marriages were arranged. That means, you didn't get to choose who your spouse is, your family did. So when God is saying that His church is His bride, He is saying that He has chosen (or arranged) to be in a sacred covenant with us. And He didn't choose us because we are awesome and perfect, He chose us because He himself is awesome and perfect and wants to be united with us forever. It's a mysterious thing, but its a sure and secure thing.

During our time here on earth, we are 'engaged' to God. He is cleansing us, sanctifying us and purifying us with His word (the Bible). We will be pure before Him, united to our Creator after our time here on Earth has finished.