Disappointment...

I live with a constant disappointment that lives within my heart, mind, and everyday life...you are probably wondering what that is...it is the constant disappointment of the father of my children.  I do not know why I gain any hope that he will do the right thing for them...for he never does!!  This always happens every year, every holiday, every birthday!  Why am I constantly surprised and disappointed??  I do not understand him!  Since we have parted ways, and he has moved on with his life in starting a life with someone else, he seems to forget that he has two children over here who need him.  Especially my daughter who remembers him.  She doesn't understand why he doesn't call her or send her anything...I don't understand it either.  And if I don't understand it, how am I supposed to help her understand it!  I get frustrated to where I want to scream at the top of my lungs that I hate him for doing this!  He is over there without a care in the world...
It was my daughters birthday on the 18th, and he did not call and it still surprises me to this day that he doesn't call her.  I don't know why!  I should be used to it and expect it!  But I always hope that the phone rings and it is him calling to wish her a happy birthday!  I cannot help but be sad, disappointed, mad, and frustrated all at the same time!  Will these feelings ever go away!?  I want them to!  I hate this feeling!  It's not fair!  The kids deserve a father, and he is denying them that privilege of knowing him...well I don't know if it is a privilege to know him...but the privilege of having a father!  My little girl wants a father so very bad!  And that is one thing I cannot give her.  I wish it were that simple...like going to the grocery store and picking out a box of cereal!  Oh, how nice that would be!  But, it is much more complicated!  It seems the older I get the less good men there are to choose from!  How is this possible?!  Is the world really going down the toilet so bad that I will be left here on this earth without a soul mate???  
I am getting off subject here!  The point that I am trying to get across in this particular post is I am so very disappointed in him!  When we met I did not fore see him being like this!  I never thought he would ever turn his back on any of his children!!!  He hasn't before, he has like 4 other kids and he has always been there for them both financially and emotionally!  I don't know why he isn't there like that for our two kids!  It seems as though as soon as he met his now wife he changed, he turned his back on our kids totally!  He signed away his rights to them and everything.  He has blamed everything on his wife of course.  He never takes any responsibility for anything that has happened!  
Is it too much to ask that he love our kids the way he should?  I should say is it too much to ask that he loves the kids the way they deserve to be loved?  What did they do so horribly wrong to deserve to be abandoned by him?  It is not their fault that it didn't work out between us...or that things ended as badly as they did!  So why take it out on them???  I just don't understand, and I don't think I ever will!  How does he sleep at night?!  He is supposed to be a man of God!  All into his religion!  How can he be such a hypocrite?!?!?!?!  UGH!  I will never know!!!  I will NEVER Understand!
I am sorry this is a angry post...I needed to let it out!