If you're that worried about STDs and ready to call it quits at the first sign, maybe this industry isn't for you. In your regular life, the girl willing to sleep with you at the club is likely doing the same with many others. Her world doesn't change if she gets an STD. But in this business, if a girl gets one and clients find out, she loses her livelihood.
Here's a reality check: higher-end providers get tested regularly. Most STDs are curable and with proper condom use the odds are minimal. Worried about HIV? Get on Truvada, and you won't get it. Concerned about other STDs? Take Doxycycline as a preventive measure, and get the HPV vaccine. I've been with over 200 escorts and haven't contracted anything. So, if you can't handle it, maybe stick to the ‘special sock’.