Most people have HSV-1 and some get cold sores and some don't. It's hard to say exactly how easy it is to spread it when there is no outbreak.
A lot of people have genital herpes and don't realize it because the symptoms/outbreaks are so mild. But they can still pass it on and the infected person's symptoms can be much worse. Women usually have worse symptoms.
I believe a lot of people that have had many partners must have herpes of some sort. People don't want to discuss this topic. They either don't want to scare themselves about sex or they have it and don't want to talk about it.
Does having Herpes I (a cold sore) give any protection against getting Herpes II (genital herpes)?
In fact it does. Studies show that the rates of infection with HSV-2 is lower for people that already have HSV-1. And it's very difficult to get both in the same area (genital, oral). From
Herpes simplex virus 1 and 2:
From here, however, the question of transmissibility gets more complicated. Acquisition of one type is more difficult--though certainly possible--if you already have the other type. This is because either type, contracted orally or genitally, causes the body to produce antibodies, some of which are active against both HSV-1 and 2. This acquired immune response gives some limited protection if the body encounters a second type. When a person with a prior HSV infection does contract the second type, the first episode tends to be less severe than when no prior antibodies are present.
Herpes - Sort the Facts from the Fiction is an excellent source of information and there is a forum there also if you need to discuss anything related to herpes.