When or How does becoming 'one flesh' occur between individuals?

I just wanted to understand how the "becoming of one flesh" or 'yoking' happens between two persons.

Is it when they have sex?
Is it when they get legally married?
Is it when they are courting (no sex involved)?

When and how does this actually take place and what would be evidence of this?

Thanks.

1 Corinthians 6:16

ESV - ¹⁶ Or do you not know that he who is joined to a prostitute becomes one body with her? For, as it is written, "The two will become one flesh.

Clarify • Share • Report • Asked October 08 2015 • Mellifluous Kandi Supporter