Ya I think its important to be honest with each other too especially if you are sharing your life together. What is the point of having secrets and grey areas that your not allowed to discuss. If the person loves you-why would they judge you??
As for people saying people with smaller numbers don't know what they like or want. That could not be farther from the truth. A friend of mine has been with up to 20 men and only had her first orgasm about 6 months ago and does not know how to give herself one. I on the other hand who has only slept with two-orgasm very easily and love to try new things with my partner and explore.
I think it is biased to say "you don't know what your missing". I think I can have 100% better sex with someone I love, someone who knows my body very well and is my equal when it comes to sexual compatibility. Everyone is different. Some people love the newness etc. I love the familiar.