That's the problem with apostate Christendom; they are ignorant and dumb! That why it was necessary for a restitution of all things!!!
What you call "apostate Christendom" is neither ignorant nor dumb. Some of the greatest thinkers in western civilization have been members of "apostate Christendom."
But while I recognize eternal marriage is nowhere explicitly taught in the New Testament, I do think it may be implicit in this passage.
Contextually, this is a trap laid for Jesus by the Sadducees. It comes in a chapter devoted to three such traps. One trap is asking Jesus what the greatest commandment is in the law. Jesus avoids the trap by giving not one commandment, but two. (His kung-fu is very strong.)
A second trap is asking if it is lawful to pay taxes to Caesar. Jesus avoids the trap by saying to render unto Caesar what is Caesar's and unto God what is God's.
I think it by looking at the context of the third question by the Sadducee as a trap that we are best able to figure out what is going on.
First, I note that if the Sadducees did not believe Jesus to be teaching marriage in heaven, there is no point to the trap. Where is the catch? Jesus just says "no" and moves on.
The trap lies in the hypothetical (probably drawn from the Apocrypha) of one woman married to seven men. It is important to the trap that it is not one man married to seven woman, but the reverse.
Now, if the Sadducees believe Jesus is teaching marriage in heaven, the trap is clear--how can one woman be married to seven men? Here on earth, she is following the law of Moses, but if each of those marriages continues in heaven, then Jesus, you have a problem.
Jesus gets out of the trap in a similar manner to the way he gets out of the other two traps. He doesn't answer their question precisely. He first parses the question by focusing on "they" (i.e., the Sadducee woman and seven husbands of the hypothetical) who are not married or given in marriage in heaven, and then immediately accuses the Sadducees of hypocrisy because they don't believe in the resurrection anyway.
In other words, Jesus acts like an apologist.
All the Best!