Hi Sammy, thank you for your question.
It is difficult to experience attraction to two people, particularly when they are two people whom you love and you don’t want to hurt. Being that one of them is your boyfriend and the other is your best friend, it is very important that you are careful, as people can be easily hurt in these situations.
Have you discussed with your boyfriend the implications of you experimenting with women, i.e. the fact that this may lead to other relationships? If yes, is he okay with that and are you okay with that? The fact that he doesn’t mind you experimenting may be that he believes it will remain simply that: an experimentation. You need to talk with him about this and you need to think about how you feel about it, i.e. do you want to be in 1, 2, or more relationships at once and if you should experiment and you find you want to start another relationship, would you be comfortable with that? Do you think you can experiment without developing stronger feelings for the other person or in a way that they will not become hurt if you don’t want it to be something more?
I would also urge you to talk to your best friend about your feelings and your confusion, as well as her feelings. How does she feel about you? Does she potentially want a physical relationship or something more with you? Is it curiosity or is there something deeper and more lasting underlying that? They are difficult questions to ask and to answer, but they need to be considered prior to embarking on a path that may lead to hurt on either side.
Best of luck.
Lorin for Alterheros