We are a new member here. Was lurking, but we want to join in the fun!
Rex has researched this topic in great detail.
When someone worries about disease what do they worry over?
#1) HSV & HPV are two common concerns. The most common forms of these are cold sores and warts. These are also transmitted thru oral contact and NOBODY uses condoms for that particular contact. Therefore the use of condoms for these infections is mute.
#2) The most common STD are bacterial. Gonorrhea, syphilis, chlamydia...
a) see number 1
b) in our age group (40-50 y/o) these are present in less than 4/100,000 in the population (CDC says so) and even then as reasonable adults we get those treated. Therefore those 3-4 random people per 100,000 only have those for a week or two in a given year.
A recent publication put the USA murder rate at 9/100,000. So you are 2-3x more likely to be murdered than get a sex disease from another adult in my age group.
3) the most hideous are HIV & HEP C. When we play we do not participate in any of the risk factors for those particular diseases. Poop and blood are the vectors for those. Yukky!
So overall, we simply don't worry. We visit the physician when we are ill, get it treated and move on. Don't you? Additionally, we have never caught any STD of any form.