The 6th day of Genesis has not happened yet. It is still future.
Gen 2 is taking place in the FIRST DAY of Gen 1
Gen 2:4 These are the generations of the heavens and of the earth when they were created, in the day that the Lord God made the earth and the heavens,
That clearly says it is in the day that God made the earth and the heavens.
Which is the first verse in the Bible and the first day.
First lets look at the verse of the creation of man in Gen 1:
27 So God created man in his own image, in the image of God created he him; male and female created he them.
At this point we have to ask God what is the Image of God and who is the HIM.
As always your bible has the answer, it is not for our own interpretation.
2 Cor 4:4 In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.
The also in Col 1 (speaking of Jesus)
15 Who is the image of the invisible God, the firstborn of every creature:
18 And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence.
So the image of God is Christ, with Jesus the head of the body, and the church is the body. And you are created in HIM (Christ)
Col 2:9-10 For in him dwelleth all the fulness of the Godhead bodily. And ye are complete in him, which is the head of all principality and power:
So God says that He is going to "create man in his own image" (the look of your own natural body)
And he says "male and female created he them"
Gen 5:1 This is the book of the generations of Adam. In the day that God created man, in the likeness of God made he him; Male and female created he them; and blessed them, and called their name Adam, in the day when they were created.
The word likeness here in verse one is described in Gen 3:22 And the Lord God said, Behold, the man is become as one of us, to know good and evil:
So we are like God, knowing good and evil, and thus the separation of the light and the darkness in the FIRST DAY of Genesis 1. So Adam was created in His likeness in the First day of Gen 1, but in His image in the Last Day (Day 6 of Gen 1), and also the last literal day of 6000 years.
As was Jesus first created as a man "But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men:"
Then after His resurrection, The image of God.
2 Pet 3:8 But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.
(In 2 Pet 3 we are told about the separation of the waters during Noah's flood, which is described as Day 2 of Gen 1) and Also we are given the length of the days of Gen 1.
1 Cor 15:45 And so it is written, The first man Adam was made a living soul (create man in his own image);the last Adam was made a quickening spirit (in the image of God created he him).
And now for why it is still future..
If you read the rest of 1 Cor 15:44-58 the answer is clear.
51 Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed,
52 In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
57 But thanks be to God, which giveth us the victory through our Lord Jesus Christ.
At this point these words from God will make more sense.
Isa 46:10 Declaring the end from the beginning, and from ancient times the things that are not yet done, saying, My counsel shall stand, and I will do all my pleasure:
Col 1:19 For it pleased the Father that in him should all fulness dwell;
John 6:40 And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day.
So Gen 1:27 I thus understand like this:
God will create everyone in His own spiritual body, looking like the persons natural body, male or female, and raise them in His image (Christ, the spiritual body), on the last day.
Eph 4:4 There is one body, and one Spirit, even as ye are called in one hope of your calling;
5 One Lord, one faith, one baptism,
6 One God and Father of all, who is above all, and through all, and in you all.