Being a Step-mom, Heartbreak and Faith in God

In 2003 I married a man with three beautiful daughters ages 2, 3 and 5 at the time. Within a year I was mommy. Around Thanksgiving 2004 I leaned down to hug my oldest good night and say I love you to which her response was "I love you too Mommy." With the other two being younger, naturally they followed their sisters responses to me. I believe that night was the best moment of my life. I was fine being mommy Kate and would never have asked for more....but unable to have my own children this was absolute music to my ears and my heart swelled for my girls even more. I was a mommy!
It is very hard being a non-biological parent in dealing with the biological father and other immediate relatives. Soon my marriage began to faulter and I became to my ex-husband nothing more than a caregiver and was to keep my parental thoughts to myself. But even still I was the girls momma and I felt that relationship with them. As the years went on the turmoil between he and I effected my relationship with the girls. After all he is their biological parent and I was never allowed to adopt the girls for one reason or another. I finally decided paper meant nothing and they were my girls always and forever.
Their father and I divorced in 2014 about 12 years after I became a part of the girls lives. Now they are 15, 16 and 19 and none of them speak to me. I can't say I was a perfect parent or that I did everything right the first, second or third times....but I believe there is far more good to remember than bad. I know being a teenager is hard and to have a second mother leave must be incredibly confusing. My faith in a God tells me that one day my girls (who are still my girls right now) will be able to open their hearts and see who I really was and am today. I can tell you it hurts deeper than any hurt I've ever felt. I could list all we did... But I'll just say I was there for too many firsts and I put all I had into enhancing their lives. Again, I was not perfect.
But what really hurts.... Is the mentality that having someone to love your biological daughter, granddaughter, niece.... Is not ok. Honestly the more people to love these precious girls I feel the better. How does that hurt them. I've never spoken ill of their father or other family members as that serves only a purpose to hurt and not enrich. I am not a bad person and I wish no harm on anyone. That will never change.
But the question arises, why? Why won't they talk to me? I miss them so much and I ache to hear their voices and about their days. I want to put the blame on someone other than them and I'm probably correct in that thought.
Having said that, why would a father allow a woman to raise his children and then cut her off? I honestly never thought he'd do that. I've always thought more highly of him than that. Only God knows.
And by God only knowing, I rest all my faith, trust and hurt in Him. For He has great plans for me and for my girls. I must rest in the peace that passes all understanding knowing my babies are and always will be babies, no matter what. I will allow God to lead and know His will, His plan is all we have.
I pray K, B and H will find life exhilarating and full of love. That they will know Christ in the deepest way a girl becoming a woman can know. I pray that God will work within them to see what is right and wrong in this world...not for my benefit but for their own.
I do wonder if I'll get to be the momma of the bride, hold my first grand baby ....just to share these joyful moments in their life...just to see them happy and growing. That is all I want, that is all I've ever wanted. I may not have been great in showing it at times but all I want is the best for them.
So, remember, when the new wife comes along or girlfriend, grandparent...whomever....look at it as a chance to have more people to love your children for there is no such thing as too much love.