“Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh” Gen 2:24 KJV
The inspired author adds this explanatory comment to Genesis 2 which teaches marriage as a Divine institution. Christ directly refers back to this passage in Mark 10:6-8 when addressing the question of marriage and divorce. The Pharisees were trying to entrap Christ on the subject and the Lord points to the Garden as the intention and plan of God. This points to the historicity of Adam and Eve.
Does this mean that there was no marriage or procreation prior to the Garden of Eden? Is this what Christ was saying? Not strictly speaking, Christ was highlighting the intention and plan of God. Did marriage as a Divine institution start in the Garden? Sure. Just as the Garden of Eden is the first revelation of God’s Law and purpose. Does this categorically rule out procreation prior to the Garden? I would suggest not. There is much procreation today which is outside (& ignorant) of the Divine ideal just as there was at the time of Christ. Any OEC position must also allow that procreation predated Genesis 2 – (although they justify this difference by referring to ‘the current creation’, an unbiblical term and simple device to enable them to reinterpret Scripture while claiming to be literalists).
Note: for discussion of Christ quoting both Gen 1 and Gen 2 in one passage see this post.