I think this is a very valuable thread to read over. I'm surprised it didn't get more attention.
I'm a proponent of going bare most of the time (not in clubs, and not for anal.... hardly ever), but that damn HPV!
I'm under 45 and will get the vaccine, but I've probably been exposed already having had vaginal intercourse with about 40 partners to date.
I've known a couple of women in the poly community in a big city have HPV on their cervix (both cleared in a couple of years). They had the same boyfriend for a little while. He was bare with one of them, and used a condom with the other.
Otherwise, in my years of non-monogamy, the moment someone has a symptom, partners are notified and and extra safety is taken till more info is given about the outbreak. Other than that HPV, I've rarely heard of a spread. It's been just individuals that have had HSV for years, and not passed it on.
I had a ureaplasma infection recently. I think I caught it receiving oral. That's one that is rarely tested for in the US, and isn't always considered an sti, sort of like a yeast infection isn't. Ureaplasma is on us already, but a person with high levels can pass that on as an infection. Like, tag..... you're it.......