Act III's Conclusion

I'm writing a play (slowly - I've been working on it for about six months). I've wanted to do that for a few years.
I'd kill to write a comedy, but I come up with few funny lines (not enough to write a whole play).
My story is a tragedy.
The plot follows a young man, who grows up and is followed by a curse. The plot is dark; it's so dark that I call it "the plot that'd make Sade proud" (it's not - only - that my brain's twisted, I was inspired by events mentioned in the press).
Act I and II need to be dark, but I had an idea for Act III; I was considering writing two Act III: one with a tragic/dark ending, and one with a lighter conclusion.
On the one hand, I think/thought that it'd be original, but now... I'm beginning to think that the less tragic act would be less courageous.

I'm writing Act II, scene 2 now. I'll see where the plot takes me.