I love how educational your "question" is. I believe in Chasity, and I was doing really great for so long, until I turned 18 and started dating this one guy.
He knew before we were dating that I was waiting for marriage, but he did not respect me in that area at all. He kept creating fights over it, and manipulating me until I gave in. He started saying things like "O.k then no kissing". Then if I still seemed not to be worried over that, he would start saying how we might as well just be friends since there's no difference from when we were friends, to when we were dating. He'd use all sorts of little tricks like that and gradually tricked me into compromising my virginity.
I was lucky not to be heartbroken by him, because he is learning to respect me and is madly in love with me, but it was pressure that did it for me. It was easier to give in, then to ruin our relationship.
I know it all sounds terrible, and I should have broken up with him before when he was pressuring me, but I felt stuck. I was convinced that I could help our relationship become better. Actually I have by alot. We are very happy now, but at what cost?