Look, not all is lost. All you have to do is impress on your kid that
they should consider the sage advice I dispense free of charge below
on what to do when they think they have found their dream partner.
This advice is not original. My friends and I got it from a senior in
high school when we were juniors. It is to the everlasting regret of
many that they ignored it.
(I) Pick a fight with your boy or girlfriend
and see how badly they can behave (it's an experiment to
establish a lower bound, recognizable to computational
complexity theorists as an "adversary argument"). This shit behavior is
what you will have to put up with from time to time in a married life
with him/her.
(II) Get to know him/her long enough to visit him/her
often at home see how his/her mom treats his/her
dad and vice-versa. That's how you will be treated in future.
The often bit is essential, so that the parents get so used to
your presence they will stop pretending!
(III) At some point, see how your inevitable crude propensities are
tolerated -- in other words, you too have to let your guard down and
stop faking -- so, try to belch after a meal, swear loudly at the TV
when the referee calls a foul the idiot shouldn't have, wear badly
fitting clothes on an important date -- then see what happens. If
nothing, DROP him/her! They don't care enough about you to stop you
from degenerating into the jakun (go back and see what this means in the
same "jokes" section) that you may be fated to become without the divine
intervention of a loving mate. On the other hand, if he/she becomes a
raving looney, DUMP him/her too. What you want for a mate is a bit like
a sympathetic correctional facility, mild rebuke followed by community
service.