That’s what is said, and it’s correct.
Imagine that. All the fuss we make about it here on earth, as if it is our only possible need and our only possible justification and the only thing that will make us happy and complete. . .
and yet for all the good it can bring when used correctly (marriage, hopefully resulting in children, a loving family learning to know, love, and serve God), marriage itself ENDS, yes ends for GOOD, on the death of a spouse “until death do us part”, and sex. . .yeah, that ends too.
Heaven is going to have something better --perfect union with Christ and each other. All of the joy, unity, perfect and incredibly faceted love–so relax. If you do have a wonderful marriage and great sex, you’ll have a great time learning the even better joys of heaven. If you don’t have a wonderful marriage, you never have sex, etc., when you get to heaven and experience the even better joys, you won’t even care about what you ‘missed on earth’. Win-win situation.