I really doubt it's dominance. Frogs aren't pack animals, they don't have societies. More likely it's just a "small moving thing: must eat" response. That's why frogs do things like eat pebbles.

On the bright side, since she didn't eat him, maybe that means he won't fit in her mouth? It could be true that they want to be together. I've heard stories on this forum about male frogs who wanted desperately to get out of their tank and into a tank with a female. Once they were put there, they were content.