Simon Kistemaker in his commentary on 1 Cor 6:17 (Baker Books (2002).
"'But the one who cleaves to the Lord is one spirit with him.'
The verse parallels the first part of the preceding verse: 'the one who cleaves to a prostitute in one body with her.' The verb 'to cleave,' used in both verses, actually means to be glued to someone. The relationship is as close as two pieces of glass lying on top of one another; it is impossible to lift the one piece from the other because the air pressure glues them together. .........
A believer becomes united with the Lord through the indwelling presence of the Holy Spirit. ....... Paul uses the present middle participle....."
Peter Naylor, in his commentary (Evangelical Press, 1996).
"Possibly recalling the command of Deuteronomy 10:20 for Israel to be joined to Jehovah, Paul insists that the believer 'Who joins himself to the Lord is one spirit with Him.' He has entered into an intimate relationship with the Lord Jesus, and the Spirit of Christ dwells in him. In the words of Romans 8:9-10, 'You are not in the flesh but in the Spirit ... Christ is in you. "
A sinner cleaves, or joins himself to a prostitute (1 Cor. 6:16) willingly, drawn by his own sinful nature. We come to Christ willingly (eg. Psalms 110:3; Matthew 11:28), but we only come because we are drawn, made willing, by God (John 6:44; 1 Corinthians 2:14). Your insistence that kollomenos is passive is the result of your incorrect understanding of the way of salvation, which is, of course, what this thread is about. If kollomenos is passive in 1 Cor. 6:17, it must surely also be passive in the preceding verse.
A thought.
In a wedding ceremony are two joining themselves or is the Lord joining them?
what therefore God did join together, let not man put asunder.'
Also it brings to mind Hosea 1:2 The beginning of the word of the LORD by Hosea. And the LORD said to Hosea, Go, take unto thee a wife of whoredoms and children of whoredoms: for the land hath committed great whoredom, departing from the LORD.