First of all, welcome to TeenHelp.

I'm sorry that hearing about your friend's experience was so difficult for you. It's difficult to hear about someone we like being affectionate with others. Unfortunately it sounds like she's really invested in the relationship she's in right now. As hard as it is, I don't think there's much you can do about that. Are there other relationships you can focus on to distract yourself from the tension in this? Perhaps there are some hobbies you enjoy that you could get more involved in. It also might be a good idea to tell your friend that you aren't up for that level of sharing. Hopefully she'll understand and not press the issue.

Take care. Please feel free to PM me if you ever need anything; my inbox is always open.