Perfect storm: started getting interested in spas, frustrated by unclear relationship status back home, on vacation so more freedom to explore, spa was right there, you had a good first time and an offer of a better second time.
If you only had CFS but no FK, DATY, or BBBJ, your odds of catching anything are near zero. For some perspective, I've been doing DFK, DATY, and BBBJ with MPAs and SPs multiple times a week for 6 years, and I'm fine.
Here is a resource that shows the likelihood of catching anything from various activities:
Know your chances | SmartSexResource