How do you just quit?

I was listening to morning prayer on the radio and a lady called in who was dealing with depression over her divorce and losing custody of her child. Any time I think about my situation, I just praise the Lord that I have my daughter! Sure she's nearly 13, mad at the world, and really stressing me out most days, but I love her. Oh my gosh I love my girl more than anything on this earth! After the station prayed for this lady they played the song "Keep Breathing" which is funny because yesterday an old friend asked me how I was and I told him that I was breathing. He told me breathing was good.

While I was listening to this song, I began to fight back tears while I was driving. There is a nagging question in my heart. I simply wonder how one just quits being a parent. I can't fathom giving up on my child. She's my beautiful angel and I'm going to love and adore and be there for her no matter what she does! How?!? How did my husband of nearly 14 years just wake up and decide that he was tired of being a dad? How could he just quit on his own baby?

It's been really sad seeing my beautiful, out going, happy go lucky child wearing a frown! I know kids sulk, but this kid, this kid has always been so happy. She was a happy little toddler no matter what her health or whether or not she could hear. She was happy living in a basement surrounded by dirt and mold. She was happy even though so many of her loved ones went away to Heaven. She was happy. 

She is such a sweet, big hearted little girl AND her own DAD broke it!

I'm working hard at forgiveness in all of this. I've always been better at forgiving people for hurting me than for hurting those that I love. It is a real struggle to forgive him for quitting on our daughter just when she's leaving her childhood years behind and moving forward into being a teenager. 

How do you just quit?!?!