My (ex-)wife had never seen a foreskin. All she knew about circumcision is what she heard in health class -- that it was done to prevent disease and make the penis "cleaner."
I learned that from her later. But when we first got together, I didn't brief her on what she was about to experience. I didn't feel the need to. Also, I have a "convertible" foreskin that rolls behind the glans on erection. So, by the time my pants were off, my penis looked like her former husband's -- cut.
About the third time we had sex, we showered the next morning. I said I was going to teach her something about me. I showed her my flaccid penis and pointed to where a foreskin usually gets cut off. She was horrified to imagine what that would to do a man/boy. Then she tested how my foreskin worked, which of course triggered a glans-exposing erection.
After that, she confided that sex with me felt so much better than with her circumcised ex. With him, she just wanted it to be over. With me, she wanted more.
She experimented with my skin from time to time, rolling it closed and open to see what effect it had on me. Of course, it made me shudder because it felt so good.
I asked her to slide her tongue into it, [Login to see the link], and she made that part of her blowjob-foreplay. Once, when she had a drink or two in her, she pumped my cock with her hand and whispered in my ear, "I'm so glad you're intact." It became her favorite "surprise" to catch me getting out of the shower, on her knees, and suck on my foreskin until I was fully erect. Sometimes she'd ask me to masturbate while she watched.
Now that we're divorced, I'm pretty sure any guy she meets will be circumcised, based on our location. Sucks for both of them.