Seahawk, I wish you the absolute best. Have you ever told your friend how you feel? Have you even approached it in a subtle manner? Have you ever asked her how she feels about other women? Have you ever asked her how she would feel if a friend hit on her? Have you ever asked how she feels about you? Patty and Lina are smart women. Listen to them.
I understand. Totally. Here is a suggestion. Make it seem like you are curious. If you see a beautiful woman (other than you two) ask her how she feels. Get an idea of how she feels about girl on girl or about MFF 3-somes.
Okay to crush on a friend but I suppose there's line of friendship we don't cross, why we don't sleep with platonic friends. The day you begin regular sex together you're no longer just friends you become amorous friends or lovers.