What are the chances of catching an STD during unprotected?

[Chiltern Line]

"Also the condom breaking incident was back in July and it was only for a minute before she realised and put a new one on. Surely a minute isn't anything to worry about? And I've not had any symptoms from that and she doesn't travel anywhere for work. Additionally, she was in good shape so obviously looked after herself and didn't have a death wish to be engaging in crazy activities like bug chasing."

You come across as someone who is perhaps on the autistic spectrum, so I'm not going to have another go at you. But honestly, your entire concept of STIs and their transmission is way, way off. How an escort looks or where she travels has nothing to do with her risk levels.

You just need to use condoms, properly and all the time until you find a regular partner, and go for an STI screen at least once per year. It's really pretty simple.