Given the premise that having someone else pay for your contraception or chosen method of family planning makes you a prostitute
To avoid having one party in any relationship reduced to prostitution, it is necessary for them to equally divide the cost of contraception, perhaps calculating it out per encounter and leaving the money on the bedside table. Remember, the more careful you are with the coin-counting, the less likely that you will actually be a whore or a john.
If you chose the rhythm method, you should make sure this applies to any calendar you use to calculate when you are ovulating. If you use a free calendar from a non-profit, assume the non-profit is paying for you to have sex/ not have sex. Obviously, you don’t want to do this, so you need to buy your own calendar — or most accurately, half of a calendar. Hence, housewives, you need to have your own personal source of income separate from your husband’s. Remember, if he pays for it, or even if you pay for it out of an account you’ve both contributed to at different times, you’re a prostitute, given the above premise.
Botkin Creative 
If one assumes (as I do not) that having sex and using contraception is a sin, then why is it the woman who is tarred with the pejoratives “slut” and “prostitute”? A woman using contraception obviously is having sex with a man. Why is he left out of this heinous equation?