Time heals everything - eventually. At 16 I knew everything and nothing was going to change my mind. And yes the thought of my parents having a sexual relationship was horrifying, they were old and just...ewww. I think it was how I was raised, nudity was bad any kind of affection was bad. I raised my kids totally opposite, if they wander into my room while I'm dressing we don't make a huge deal of it whatever they came to see me about is dealth with and we all move on. Hugs and kisses are the best thing ever (my oldest remains affectionate to this day - he gets upset when he doesn't get his morning hug and kiss). I've always been open and honest about sex with them. Any questions they asked were answered truthfully. It's worked out in the end. My oldest son who is 17 is fine with my relationship with J. My 13 year old, well not so much. But, he's always been a bit more "clingy" than his brother. I think he's afraid of the changes that have happened. Both my boys have known J for some time 3 years at least so that helped some. I just try to be as supportive as I can to my youngest show him that I still love him and that nothing between us has changed and I'll love him no matter what. He seems to be coming around but only time will tell.
Just tell her that you love her and then prove it to her. Be as honest as possible and giver her the time she needs to find her way.
Where there is love there is life.