The Sadducees asked who would be married to who in a tricky question. Jesus solves this problem by there being no marriage. It also makes sense that the resurrected people would be similar to the other beings who live in Heaven, the angels.
Marriage is not just sex. A bunch of things can follow from this statement. Who knows what is meant by this? I think something is implied that assumes knowing the context. Do Angels have sex? From other sources, sometimes yes. Sometimes no.
I thought there were a lot of verses in the New Testament that talk about people going to Heaven.... what is odd though is that the Sadducees are asking Jesus about the resurrection even though they don't believe in the resurrection.... (Matthew 22:23)
Don't forget that this text is in the Bible. It's supposed to be a theological slam dunk for Jesus, and the Sadducees looking like idiots. So words have been put in the Sadducees mouth, they may or may not have said.
That said, within Judaism exegetic debates, and arguing about Biblical interpretation is encouraged and part of the religion. Which sets it apart from Christianity. So for all we know the Sadducees weren't agreeing that we go to heaven. They might just be arguing hypotheticals or playing the devils advocate.
Fun fact, within Judaism, this is what Satan is. He's the devils advocate who asks the faithful probing questions and tests their theology. Satan in Judaism isn't a bad person. It's a role. Anybody can play the role of Satan in a debate. It's a morally neutral position. It was only much later transformed into an evil force. But I digress.
https://en.wikipedia.org/wiki/Heaven_in_Christianity
The Bible is all over the place on what happens after we die.
Judaism was undergoing a transformation during this period. This movement of transformation is what created Christianity.
The Sadducees represent the old and traditional Judaism. They were the priestly class, so temple Rabbis.
They did not believe in Heaven. They did believe in the afterlife, in Sheol. Which is the same idea as we find in Pagan Greek or Roman religion. It's a ghostly dull existence. It's also a place you go no matter if you were a good person or not. No sex and no fun.
To the Sadducees and traditional Judaism (ie the Old Testament) our life on Earth is the main event.
The Pharisees and Christians (and Essenes) are a break with this. They do argue for a life after death.
This idea that good people go to Heaven and bad to Hell (Sheol) is not an original Christian belief. That comes much later.
Strictly speaking it's a theological confused mess. If anybody at all goes to Hell, that means that the Sadducees were right, and nobody goes to Heaven. If anybody goes to Heaven that means the Pharisees were right, and nobody goes to Hell. Jesus in the Bible slides back and forward between these, and also the third option, Eternal Life on Earth. So nobody goes to either Heaven or Hell.
https://en.wikipedia.org/wiki/Christian_views_on_Hell
The Bible contains all of these beliefs side by side.
My money is on that Jesus is dodging the question.
I think saying there is no marriage in Heaven is a solution to the problem. Do you think Jesus had to think up a solution to their question while having some form of marriage in Heaven? BTW marriage implies sex and sex can imply children (including in Mormonism).
I think we're missing some critical context. I don't think anybody knows.
For Biblical scholars these passages in the Bible are interesting in that they are found in the Bible at all. It means it wasn't settled at that time. This is religion evolving on the page. That's cool!