We have remarked previously that kids construct their reality based on what they see in their parents' behaviors.
We have never hesitated to hug and kiss in the presence of our daughter. Casual nudity in our home was and remains the norm. She was told that mom and dad needed private time, and that was the only time our bedroom door was locked. She always had age appropriate information on sex. We told her that when she was ready, we preferred that she have sex under our roof where she--and not the boy--was in control of the situation.
When we went on our first clothing-optional vacation, we told her. When we started having adults over for pool parties (we made sure she had friends to stay with that evening), she didn't take long to figure it out. Nor did it particularly phase her.
Why? Because what matters to her is that we are her parents, we are still together, we are still in love. In an era of broken families, blended families, single parent families, second and third marriages, step-whatevers, we have been constants and we have been her parents.
She is bi-situational, yet she is somewhat prudish. She does not want our lifestyle at this point--she wants a romantic marriage-- yet she wants our happiness.