MB:
Do the math. That sort of behavior will get you killed since the advent of AIDS.
One doesn't have to drag out any moral arguments or ethics to figure out that that sort of behavior is A VERY BAD IDEA in this day & age.
Reducing the likelihood by 85% of transmission of HIV with the use of condoms does one no good if you double/triple/quadruple/etc-down on the number of folks you get jiggy* with.
Not to mention the baker's dozen of other STDs and other blood, fluid, and feces-borne illnesses (Hepatitis, HPV, cervical cancer, etc.) not so dramatic as AIDS. A simple case of HPV or the clap can render the afflicted sterile** and herpes will, in the immortal words of Eddie Murphy, "Be with you forever, like luggage."
The most "sex positive" demographic, (homosexual men) lose roughly half their life span, on average, due to their "sex positive" activities. And the last years of their average of 35-37 years are spent dying. Hoo-freakin'-ray for halved lifespans and lingering deaths!
Also, trusting folks to be honest when they already show they are at odds with conventional ideas of morality, ethics, and social mores is a fool's wager.
* Or, since the OP referred to large types, "get jiggly" might be more appropriate.
** Not much spoken about, but probably second only to a woman's age as a cause for sterility, but applicable to both sexes.
