What is Biblical marriage?

Gen 2:24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.

Mat 19:5 And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh?
Mat 19:6 Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder.

You find a woman you like and want to live with, leave your parents home to be with your wife where the two become one flesh (in the bed room).

From there cultures add on a huge amount of unnecessary things.

No, it's formal because Paul is speaking as a church official in a position of authority. If he was talking to one of his buddies about his hunting experience in the woods one random morning- that's not Paul talking in his official capacity as an Apostle... unless he worked it into a sermon somehow... but surely you get the point?

I agree with that.

So this verse basically reads like "forbidding to become one flesh?"

1 Timothy 4:3
3 Forbidding to marry, and commanding to abstain from meats, which God hath created to be received with thanksgiving of them which believe and know the truth.

Yeah, that's called fornication unless there's some formal marriage agreement.

Not really. I think many people "become one flesh" through sex but aren't married.

G1060
γαμέω
gameō
Thayer Definition:
1) to lead in marriage, take to wife
1a) to get married, to marry
1b) to give one’s self in marriage
2) to give a daughter in marriage
Part of Speech: verb
A Related Word by Thayer’s/Strong’s Number: from G1062
Citing in TDNT: 1:648, 111

I think the verse is saying actual legal marriages would be or were being forbidden but I don't know where or what place the verse was addressing.

Nope. Christ was describing marriage not fornication. Fornication is similar but the people who do it aren't Christians who love each other, love God and Christ and want their union to be a marriage. In original marriage there w as no judge, white dress, cake or throwing rice etc.

I believe the whole “sex before marriage” is a false idea that is not biblical. Sex is the marriage. Once sex occurs, the man is bound to the woman for life.

Christ was talking about the Genesis account which doesn't mention any bedroom. You'll also notice "cleave to his wife" comes before the two becoming one flesh.
Christians fornicate too, and it's devastating to their walk with God and everything else. If they want their union to be a marriage, then there has to be some kind of attestation to that beforehand.
Absolutely nuts, and precludes the concept of fornication.

Christ did not speak of any such thing nor did Adam and Eve have it.

When a man and woman consummated their relationship it was over. When the contract was signed by the bride's father and the bridegroom they were essentially married at that point. No priests were involved except for the party which they may have been invited as Jesus was at Cana.

Sure it does. As far as the secular world is concerned these are key ingredients. But that does not minimize what you said about matters of the heart.

That's easy too. Any talk of divorce must be made taboo right from the start.

We aren't discussing Wat the secular world views as part of marriage because we already know that. We are talking about biblical marriage, especially the first marriage described and is that still a valid way to have a real marriage in God's eyes.

Unfortunately, all aspects of marriage need to be addressed by Christians. And there is nothing evil in either ceremonies or documents. Indeed the Bible speaks about the Marriage Feast at the Marriage of the Lamb. Ideally God is the one who brings the bride to the bridegroom (e.g. Adam and Eve). But Abraham had to send his servant on a long journey to make it happen for Isaac. And Ruth had to go through some activities before her marriage. And what about Esther?

Yeah, when God rips out somebodies rib and creates a person specifically to be a mans wife, sure- if that happens, that's valid. Jumping in bed with somebody and then assuming you're married to that person is absolutely not.

Rachel was promised to Jacob.
The wedding feast occurred.
Jacob married (through sex) Leah instead, without knowing it was Leah.
Seven years later, Jacob married Leah.

22 And Laban gathered together all the men of the place, and made a feast.
23 And it came to pass in the evening, that he took Leah his daughter, and brought her to him; and he went in unto her.
24 And Laban gave unto his daughter Leah Zilpah his maid for an handmaid.
25 And it came to pass, that in the morning, behold, it was Leah: and he said to Laban, What is this thou hast done unto me? did not I serve with thee for Rachel? wherefore then hast thou beguiled me?
26 And Laban said, It must not be so done in our country, to give the younger before the firstborn.
27 Fulfil her week, and we will give thee this also for the service which thou shalt serve with me yet seven other years.
28 And Jacob did so, and fulfilled her week: and he gave him Rachel his daughter to wife also.

The wedding analogy was used throughout the gospels by Jesus like "You were bought with a price," for the brides cost the bridegroom a lot of something whether it was material things, animals, money. So it actually made the marriage more secure lol, for the bridegroom remembers what she cost him.

It was with Adam and Eve. Christ spoke of marriage using their example yet you think Jesus was talking about fornication? I would love to see what Jesus would say to you about that.

Mat 19:5 And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh?
Mat 19:6 Wherefore they are no more twain, but one flesh. What therefore God hath joined together , let not man put asunder.

Let man also be quiet!

See, God puts together that type of marriage. He is not involved when it is simply fornication.

Before jumping in bed with someone, stop and think, are you ready to be bound to that person for life.