According to Abraham Maslow hierarchy of needs, sex appears to be a subset of needs which is amongst the basic needs of man, and in each of those needs, which are basic, are food and shelter and, I do not see why we can not pay for sex, if we can pay for the food we eat and also for the clothes we wear.
I am not trying to incite any negative narrative here, I am just saying my mind, maybe, I am speaking from the way the society is, because when I was young, there are some things that were not so clear to me, but growing up has taught me so many things which i think I didn't know earlier.
Most importantly, paying for sex depends on what was the agreement on ground, and to be frank, food are sold in eatery, clothes are sold also, and it is that same way that we have places where people go to clear their head at night, pay for sex and have it, and also, it does take place in the day time.
In some relationship, either the man or the woman, who are on it, are paying the other, I have seen a relationship where the woman is paying the man each time they met, sometimes, they would traveled to a far away place, to enjoy themselves and on coming back, the guy would be on so much money.
Thereafter, I have also seen a relationship where the man is paying the woman, and a week would not get by without him sending money to the woman, just because he doesn't want her to get angry a bit, he wants her to always be happy for him, so that she would care for him as well, when he wants someone to rub his head.
Yet, it is all love and I am not judging anyone on which part they played, it's only understandable to me now, because, before I didn't have that understanding of these things, now I have realized that, they're something's in life that we do not have the best way to handle, but people just played it in the way it suits them.
To be frank, giving money to a person we love isn't bad at all, but it is not a doubting matter also to say that, people are paying for sex, sometimes, most of them wouldn't want to do it, but because, when they feels like having it, they just can't escape the basic needs.
Love is something big, I must said it again, and when it comes to love, a person isn't intelligent at all, unless, he or she is hurt, that's when they can begin to understand themselves and start thinking otherwise.
Yet, I am not different in any of these, I have paid for sex in some occasions and they're also times I don't pay for sex, because someone else was paying me.
This is my entry in the weekend engagement experience topics by 
Images are mine.