In yaoi (and in general literature) it's easy to find many cliches. I guess that kind of topics are interesting to explore as a writer.
In any case, it's not about the times the story has been repeated but how is it told what makes a good work or an average one.
I've read superb mangas with a very cliche plot that were just so well written you didn't even care it was overused.
So I'd give it a change. Worse case scenario, it'd be just another tragic manga which I'll forget in no time. But there's always the chance it will blow my mind, why not take it?
That's my two cents anyway.
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I AGREE WITH YOU 100%!!! ヾ(☆▽☆)
hmm. this is very cliche to say the least... this trope has been done so many times...