There is a book called "Clownfishes" by Joyce Wilkerson. I don't have my copy at home right now as a friend is borrowing it but I recall in there somewhere she discusses this a bit in terms of causes and solutions. I believe it is this book, though I may be wrong...
In my view, a female will reject a male clownfish if he is not doing his "job" and living up to her ridiculous expectations (not too different from people
). Part of the issue is that he is weak now because she is bullying him, so to her he looks weak and thus there is more reason to keep picking on him.
Personally I would give them some time apart, a trial separation if you will. Move the male out to a quarantine, feed him and get him back to help, let her chill the frig out about whatever set her off and reintroduce him like you would a new mate. She'll beat up on him again for a few days to establish dominance but they may pair again.