..but then you just seek to deflect the issue .. rather than discuss the
immorality of sex before marriage.
I have a daughter. I will advice her to have sex with her boyfriend before long term commitments like marriage or even only buying a house together, to make sure they are compatible in bed as well and not just in personality.
Sex is a big, and very important, aspect of romance and partnership.
Being stuck in a marriage with an incompatible / unsatisfying sex-life, is psychologically damaging.
There is nothing wrong with having sex between consenting adults.
As with everything, off course, one should approach things reasonably and responsibly.
I would very much advice against engaging in long term commitments before making sure you are sexually compatible.
That, and also the simple matter that sex is a physical expression of love.
There's nothing unnatural or immoral about it.