Life changes all the time

The leaves are changing colors, nice rich golden browns, oranges and even some yellow.   The reflection in the water makes me remember that life does changes all the time.  My life has been changing and I don't wake up sad anymore.  I have been dating someone who has showed me there are still good men out there.  But somedays I still have my doubts...
On thursday my daughter and my ex will take a trip overseas.  My daughter will meet his fiancee.   It was supposed to be a wedding but his fiancee changed her mind, as it is, he is still making the trip with my daughter.   It will be nice for her to take a vacation and get to see another country. It is nice from him to take her.  What is bothering me is that to this day, my daughter does not realize what kind of man her father is.  In her eyes, he is a great guy; who, despite she been, sadly, a witness of the contrary, she still thinks he is the best one.  I can't really say anything, she does not need to know the nightmare I went through. 
But I asked myself, if this wise?   By keeping silent...am I doing the right thing?  Or am I harming her more?   Does she needs to know he spent her entire college fund, that one day he will say he loved me and the next that he didn't or the time I spent in the hospital bed with damage to my ribs?  That he won't tell her to her face but she will belittle and critize her behind her back?
Or is he remotely right and I am the worst one of us two?