There's a huge difference between 'can't' and won't' but we (or at least me) use them as if there wasn't. Why? Who knows. I know that a lot of times I use it as an excuse:
"I can't write today, it's Father's Day."
"I can't finish that chapter, I don't have a character figured out."
But what I really mean is that I won't do these things because, well, I won't.
The same idea, I think, like so many ideas do, lends itself well to love.
"I can't be in a relationship right now."
"I can't call him/her tonight, I'm too busy."
"I can't see you today."
When in love, when writing, when living, why "can't" we do thing?
Or, better yet, why "won't" we?