It's hard to pin down where sexual confidence comes from. Easy to see where it can be lost:those first few encounters can be crucial. A bad experience can be very damaging.

And just being that bit behind your peers has a knock on effect: if you were just a bit less adventurous than they were and held back on first date, then next time, you had less street cred, less experience than they had, so you would hold back a bit more. The effect is cumulative: by the time you get to 40, you're out of sight as far as knowledge and practice go. How can you get back from there without help?

Chuck in a few other disturbing factors: worried about sexuality, gender, illness, having to care for others, abuse, all these feed into the process and make you scared of sex. Or of finding out who you really are, something that tends to come out of a sexual relationship, at least, out of a fulfilling one.