its a bullshit excuse!
I know you will blame yourself, everybody does and she will feed on this during the breakup.
"You work too hard, Your too dedicated, you spend too much time at the gym, everthing else is more important than me...."
Its just Bullshit
Countless Women spend most of their lives looking for a guy like you with those traits and charateristics. Many will be happy, dedicated and loyal, but many turn on you and use them against you to give themselves justification in their behavior.
Try very hard to ease your mind and don't say that these traits led to the breakup. Other unknown, to me at least, factors did.
She will regret it later when she sees how many real loosers are out there.
You are a winner!