Come to think of it. It did look like Bulk Biceps had a bit of a crush on Fluttershy, But Didn't Know How to express it, in the Episode "Rainbow Falls". Maybe that's why He was afraid of Butterflies in "Flight to the Finish" They were a reminder of His.... Problem.
I mean He's not exactly What one would consider to Be Fluttershy's Idea of Her Ideal Stallion.