Sounds good Lmo. The only thing I am not sure about is the offer of finding a counselor. If this isn't something you've disgussed before or maybe it's not something she is open to it may seem like you are apologizing but calling her crazy at the same time. Just looking at it from her possible point of view being she is hurting.

If the letter re-opens a door for you two to talk then you could bring up counseling. Maybe saying how it helped you to deal with your breakup and since she is hurting just as much then it might really help her.
Hugs and best wishes,
Heidu

The highest reward for a person's toil is not what they get for it, but what they become by it.
John Ruskin