Adultery, abandonment, divorce... not really my thing and not what I was expecting. 
 I don't understand why Hadley had to forgive her father's actions. In my opinion what he did is pretty hard to forgive and not something a person worthy of her forgiveness would do. It showed a complete selfish attitude when everything was combined. There were so many things I took issue with in various degrees, it's not worth listing them all. Yes, she needs to make her peace with the situation and develop a relationship with her father again for her own sake but give the girl more time. She had a lot to deal with in the past year. Peace also doesn't necessarily mean she has to condone what had happened. 
 Also, why wasn't she also upset with the women her dad was marrying. She did get involved with a married man with children after all. 
 As someone from a broken home that had a lot of painful issues resulting from it, I can say that I sympathize and think it would be hard to brush aside the situation so easily. The ending seemed very unrealistic and not that helpful for teenagers struggling with forgiveness. It was more of an ideal version of the possible outcomes. The realization that your parents may not be who you want them to be, can be a hard thing to deal with. Hadley was obviously very upset, to the point of developing new phobias. 
 Just saying....