Am I stone-hearted?

Just now, a friend of mine told me that my ex-girlfriend was in hospital now because of Dengue.
He knew about our relationship.
He said, "Who never makes mistake before..."
He asked me to forgive her.
He asked me to give her a call or sms her to ask about her condition.
This would answer my doubt on why her mother was so worry until she called me and asked me to tell her "roommate" to take care of her a few days ago.
I did not do what my friend told me.
When I thought about the ways she treated me and hurt me last time, I still could not forgive her.
I think I still cannot totally let it go.
I wonder if I could forgive her and visit her if her condition worsen.
I hope she will recover soon...
Now, I may be a little stone-hearted already but I hope I would not become a blackhearted person in the future.