In love with my best friend?

I’m in love with my best guy friend but he has a crush on a girl from the gym we both go to. Every day I fear he’ll start talking to her (for now they don’t know each other). Recently he became friends with some of her friends from the gym (who often go out together) and I’m afraid that they’re gonna invite him as well, he’ll meet her and sparkles between them will happen. I don’t know what to do, I’ve been thinking about befriending her and explaining the situation so she doesn’t do anything with him…
In love with my best friend?
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