My best friend (23F) said she got off while thinking of my boyfriend (20M) and I (23F) having sex?

My boyfriend and I have been together over 6 months now and my best friend hasn't been the most supportive of our relationship during this time. Throughout she has made it very clear to me that she hates him and has made many other rude unwarranted comments about his appearance. She recently told me that after him and I publicly posted photos stating that we were together that she was enraged and disgusted. She said the entire night she was raging but that she was also coincidentally extremely horny. It got to the point where she said she was masturbating while thinking of him and I having sex, for which she said she felt very guilty and apparently repulsed as she hates him. Later on in the conversation she asked what positions we've tried and how big his dick is. I can't help but feel really disgusted and disrespected. She's been my friend for years and never been in a relationship but I feel like this crosses a line. I don't know how to approach the friendship from here on