I think you had a right to break up with her once you found out, but you could have handled it better. Keep in mind, this was still a person that loved you and shared a lot of experiences with you.
There was no need to be that cruel. You could have just said something like, "I'm sorry, I wish you had told me up front, but having my own biological children is important to me, so this is kind of a deal breaker."
I mean, she was having suicidal thoughts. Do you really want to be responsible for her going off the edge?