The Quran (Nur(24):3) is forbidding that kind of mix-up, but people take that laxly, obviously.
Allah likes to accept when people repent (Nisa(4):27). But, how people commit their out-of-wedlock sex, is a system. I suspect they would qualify in the category of repenting, as there seems to be no remorse there. All is in the plan. "Having sex with promiscuous girls, then marrying a chaste girl." (Or, worse, that habit might go on, rather than terminating after marrying.)
Transmitting sexually-transmittable illnesses to their wives, too.
A half-serious (but probably optimal) relief (I propose) to that problem.
This relief is not for Islamic states (and probably is "innovative"/bidah), but Western nations (which allow sex out-of-wedlock) might think this seriously, as a policy.
The rule is to not allow a muslim to have sex out-of-wedlock, without listing that in a state-registry. For example, if Shaban will sleep with Helga Xy, first let him report that to Deutsches Sth.
That would allow him to boast his "prowess," with a proven tally.
That would allow chaste girls to know the history of that who wants to marry.
States need to have some official spelling for all visitors/citizens, to find names right.
In the "worst case," if most males would like to sleep with Helga, chaste girls would not marry, or they might think opting for polygyny -- co-wives, by marrying with chaste men.
Conquering Helga is Shaban's option, but that might look like Tariq Bin Ziyad burning the ships while to conquer Europe. Not to return to marry a chaste girl -- unless (but, truly) having remorse.
With a wish to not have out-of-wedlock sex (even if the current target girl would still not accept to marry him, that is). But lots of "casanovas" lie, routinely. So, hard to guess.
Helga might look as more human to Shaban (rather than only a temporary fun thing), if Shaban will keep there. That might help against some crimes happening, abusively.
What I propose, is not violating the Islamic rules against gossip.
Such people most often boast their sins, any way. Islam is not counting that as "gossip" (giybet), if the sin was openly known. (Not known by all, perhaps. But that is the point in telling.) Those who witness the cases through time, know that. But while to marry, that is not necessarily told to the prospective victim (the girl to marry).
Committing the sins openly, is worse than committing without telling to others.
Sex is not alone, in any case. Besides, if willing not to sin, then opt for chastity.
Otherwise, other people risk paying with pains (the "thing," Helga), or sins (like the parents of the boy who know him but would not confess, not to ruin his "reputation.")