Kay

“Or perhaps you don’t know that the man who joins his body to a prostitute becomes physically one with her? The scripture says quite plainly, “The two will become one body.” But he who joins himself to the Lord becomes spiritually one with him.” 1 Cor. 6:16-17
“”For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh.”This is a profound mystery—but I am talking about Christ and the church.” Eph.5:31-32

The more I compare these verses, I do not think that in Eph. 5 Paul is referring to Christ and the Bride (Church). I think the mystery is becoming physically and spiritually one-flesh. As in the head/body analogy – as Christ is the head of the Church.