If his ‘needs’ aren’t being met by his wife why doesn’t he go to a prostitute instead of tapping up the local physio?
I have thought about this and concluded that it’s because he has no chance of getting any freebies from a prostitute. (Mind you, £3k would have bought him a fair few sessions from a prostitute!) He’s just think that he’s a right snake and I reckon he likes the power over her, he can easily try to blackmail her if she’s got stuff to lose. Prostitutes can refuse to do stuff, so they have control (unless controlled by a pimp/drug habit etc)
(Spoiler alert) In Episode 2 He had a thing about being clean too, so probably thinks that prostitutes are “dirty” especially if they are having sex with so many people. Whereas the physio, presumably, only had sex with her husband at that time so seen as more “virtuous”. Maybe he also liked the power trip of fucking someone else’s wife without their knowledge.
I skipped through the episodes and later on she said that the physical part was actually quite enjoyable, but the minute she gets naked he takes one look and turns the light off - what a bloody cheek! That would have turned me right off and I would have yelled “what, you don’t like the sight of stretch marks, eh, does it remind you that I’m somebody’s mum?!” And told him to fuck himself, and done a big flounce 