Maybe her partner doesn't expect that. There are 2 girls I've seen multiple times who both have LT partners who are fully aware of their excepting activities. And another I used to see who's partner was aware and she did incalls at their shared houses in the bedroom they had set up as a kinky sex room.
Her boyfriend would need to take her out of London so that she doesn't bump into any hot rich men.
Then he needs to put her in a position where she is more dependant on him emotionally and even financially while
living an easier life in a rural area, if she gets bored he needs to take on an unexpected holiday.
This will be extremely difficult as women who have had a stadium of boyfriends
find it harder to bond.
If he can keep this up for 3 years she will be in her early 30's and won't have the energy or competitive edge
to be a hoe in the in the city. plus, 3 years from now London will be even tougher for a single person so she would stay with him
especially if he has enough money to take care of her while she is pregnant.
He has a lot of work to do because he gets bored easily and loves cock.
He has his work cut out because tyfanny appears to be hard work.