Having managed an establishment (in my past adventures) were the lines between brothel, strip club and waterfront tavern blurred, my take on it is that the lifestyle would actually improve.
You would be completely and utterly amazed at the number of guys that stop by to get a couple of beers and to look at some pussy and (more often than not) a BJ if the mood strikes. All in the name of a cold beer after work. If you include the theories of supply and demand associated with legalized prostitution, here is what will happen. You now have a place where all the single guy's of questionable honor will congregate, plus all the cheating males and, not to mention, a certain percentages of the swinging rookies. recall just how often around here do we see the question, "What about getting an escort".
About a million and one brothels will pop up all over the place. They, like the adult toy/video store industry will span a range of classiness. From the 1000/hour Nevada type to the 20 dollar sticky floor places. Most, if not all will include a liquor liscense and that is where all the people we bitch about will gravitate to. Booze + $$$ = certainty of sexual activity
Who is left for the clubs? Us folks ,like the membership here

, that want a little more than just 3.2 nano seconds (and a $20) to a wet noodle! I am sure there will be some club owners that try to incorporate both, but they will soon either fold or turn to straight whore houses for the same reasons listed in the other thread.
Think about it, which does society have more knowledge of, prostitution or swinging? Open the legal door and the common thought will be to gravitate either to prostitution (leaving us alone) or shun it. Those that shun it will either be the type we want to swing with, or morally replused and stay home (out of our hair). Thus the swinging life improves..win-win