Context is key when dealing with the "L" word..
One can love someone who is not their lover
One can have a lover that they are not in love with...
You are of course correct and the term lover has traditionally covered someone who you have a sexual/emotional relationship with outside of marriage. Is this definition a little dated I suspect it is? Then there is the term 'making love'?
I was really commenting that I didn't think I had seen it used before whenever this topic crops up and it does with remarkable regularity going back donkeys. Which in turn led me to the 'L' word.
The association between love and sex is a complex subject, the discussion, of which is beyond this answer and indeed the two will be closely linked in ‘relationships’. They can of course also exist as separate entities. Many punters reading are in loving relationships but seek sex elsewhere. The majority of punters separate the two unless EAS creeps in!
When a punter and wg first meet it is a purely sexual encounter albeit a distorted one due to the financial nature of it. Even more so than a typical one night stand. The quality of such an encounter will hopefully be satisfactory for the punter, but for the SP will likely be very average/tolerable at best.
But just occasionally a punter will push the right buttons and even more occasionally the SP will then seek a non monetary arrangement, to which the punter agrees. Whilst this is not common it is probably commoner than many think? Call it 'lover' or 'fuck buddy' as you wish
Most are in my experience fairly short lived for a whole host of reasons, one of which is when either one or both partners feel it is developing into something else ‘emotion wise’ and that is not what they are looking for.
However in an even smaller number of cases and if the ‘L’ word starts to rear its head (on both sides) then the relationship may develop into something else. If it does then the hurdles of "can she trust a punter" and "can he cope with her shagging other men" have to be overcome. That final hurdle often results in the demise of a further chunk of punter/wg relationships and we are left with an even smaller number of successes. But they do happen.