Don't know the full story here.. But if he's coming over for sex and you met in a transactional relationship manner...
Then surely hes just taking the opportunity?
Not sure what this has to do with marriage but I don't want you to get hurt..
Ive had clients genuinely interested in me before and they would NEVER not pay for a session. They would ask me out on a date if they have developed feelings.
It's completely fine, a bonus really, to have affection but please never stop charging.
If you get a proposal that WON'T be because you gave it for free. The direct opposite usually happens..
I think you need to learn a bit more about how men think.