This is difficult. VERY difficult. But here is what I am going to say.
Think about which person has known you the longest. The one that has known you the longest probably will be the most flexible. That is an option.
Also, if I were you, this is what I would do. Tell your friend that your boyfriend has made plans the same day as well. Spend the morning with her, and the "romantic evening" with your boyfriend. Also, explain the situation to your boyfriend.
As I always say, the people that really love you will continue to love you no matter what you do!
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