if he wasn’t exposed by me getting chlamydia and gonorrhoea
So those, to the best of my knowledge, are not sti's that get around condoms easily.
Which would make me think it was not protected sex
Which is - from reading UK punting, reviews by prostitute users - very unusual in the UK.
(Most punters don't even want to have unprotected sex with prostitutes, going by that site. They consider it unwise, given how many men the sex workers are having sex with and the fact that some of them might be drug users).
(Think about it; StI's are common. They are particularly common among people who have sex with multiple partners (men who use sex workers),.
The sex workers aim is to make money, their pimps/handlers etc (if they have them)'s aim is to make money. You don't make money when you're out of action with a nasty dose for days/weeks.
You also risk a punter accusing you of infecting them with stds and writing that on UK punting or similar sites. I've seen a UK punting post claiming a prostitute had a herpes blister in her thigh - which she actually responded to, saying it wasn't a herpes blister - and their "conversation" became an increasingly angry, vitriolic, nasty exchange on that site Essentially he was damaging her business by saying that. So it's not in the interests of sex workers to get or be accused of having STDs).
Was it overseas that he claims this one instance of sex with a prostitute was?
Because otherwise I'd seriously doubt his story.
It sounds like something he made up because he'd been cheating on you with at least one person and wasn't ready to leave yet/at that point.