Oh sadness

Motherhood is the one thing that just keeps reminding me of my shortcomings...
Today D was irritated by something her daddy was doing. She kept saying, "No, Dad!" but laughing and then when he wouldn't stop, she hit him.
He was M.A.D. So, he immediately reprimanded her and gave her a time out.
It is really hard to watch D in time out. He had her standing in the corner of the room facing the corner. She was crying her eyes out and calling out to me, of course.
I had to gently remind her that I could not go pick her up because she had hit her dad and that was not acceptable. Soo sad.
This particular incident, in and of itself, is not what really saddens me. What really saddens me is the fact that her temper, hot-headedness and tendency to lash out and thrash things is a result of watching me. I know this because she had exhibited this temper early when she was just maybe 10 months old. And at that time I realized she was acting out according to what she would see from me. Since then, I had really worked hard at controlling my temper and I have seen her temper diminish.
However, now that she is getting older I am finding it harder and harder to control my temper. And the fact that if she hits me, my quick reaction is to hit her back while saying, "See? That doesn't feel very good does it? So, don't hit mommy." Umm..WRONG. I know, I know it's wrong yet I am just not able to control myself. I mean, I am able to but am having a hard time remembering.
When she is doing something wrong, my automatic reaction is to smack her hand or her arm or her bottom to get my point across. Also probably to assuage my own temper.

AAAARRGGGHH!! I struggle. But I don't want her to suffer through time outs. It's so sad and I know it's because of me. The guilt...