In the old days of the Internet, there was a Cost of Sex Calculator at http://www.costofsex.com/. Unfortunately, it is no longer online. Even more unfortunately, it was last up so far back (2004 - the only reference I can find to it) that the Wayback Machine does not archive it.
I have thus taken it upon myself to recreate it as best as I remember (albeit using monthly numbers instead of weekly for greater accuracy [e.g. some people may have sex less than once a week and in general weekly variance is going to exceed monthly]). And here it shall stay - until Blogspot goes down, uCalc goes down and/or uCalc decides to no longer support calculators created on expired free trials.
Of course, the calculator is not gender neutral, because we know the dynamics of non-heterosexual relationships are different.
If uCalc does down or restricts my account, here're the relevant variables:
Number of times a month you have sex with her
Amount of money you spend on her every month
Number of hours a month you spend in pointless conversations/arguments with her
Number of hours a month you spend doing things you don't want to do for/with her
Hourly wage
Someone suggested I make multiple calculators to compare "diy vs wife vs hooker vs sugar baby etc", but the calculator above can be used for such purposes as well, once one understands how to impute the differing cost/time inputs involved.