I know exactly how you feel. I'm constantly intimidating all the incompetent morons around me (I'm looking at you, Barry), which I surmise is why I am rarely invited to parties (I'm looking at you, Barry).
And yes, I think there could be some truth to the notion that dudes--customarily able to rely on superior physical strength, if nothing else, to provide at least SOME sense of identity and self worth in the relationship--freak out if they realize you could totally take them.
But I'd caution you not to risk conflating correlation with causation. There could be any number of other reasons you can't get a guy, though I won't speculate, except parenthetically (body odor?). Causation/Correlation conflation has been the ruination of many a romantic preoccupation. Also it sucks in science.
Even if your muscles are turning some guys away, I'd say stick with it. If you enjoy it and it's a part of your life, you'll eventually run into someone who loves you for precisely that. And in the meantime, wear billowy clothing and ask your dates if they could "possibly open this stubborn ketchup bottle."
Unless you look like the woman below. If you look like the woman below, my advice is very different.