I don't understand how my husband, let his x step daughter come in to his marriage of almost five years,

She came to our wedding unexpectedly, I didn't even know her , she got drunk and so was my husband ( her x step dad), he hardly spent any time with me on our wedding day , they were all over each other , when she got ready to leave with her husband then he didn't want her to go, here I am alone 

About six weeks after we were married he wanted to go spend time with her on new year's Eve  and I said we r not going to c her and he got very mean about and said ate you trying to keep me from seeing my kid I said no but wait she isn't your kid she is your x step child, I tried to explain to him we are married now , she is your past , we have a future together, he said let me tell u something no one but no one will ever come between me and my kid meaning his x step child

I said I am not trying g to do that but this is our first new year's together why can't we spent it alone

He said I want to go see her

So as years has went by they didn't have much to do with one another 

Now she is back in his life again, to where we are getting a divorce over his x step child, he even got rid of his brand new truck, losing g his marriage, every thing because of this x step kid, his x step child hadn't been there for him at all I have been there 

His real daughter cuss me out he called his x step child and said you don't have to worry about what my wife says you can call me anytime, that hurt, 

So I feel second best now in this marriage, this to me isn't right

He said I raised her from 6 to 17, and she is my kid, and no one is coming between tbem,I understand he was in another marriage and he help raise her but that was years and years ago 

I have always been told u have to let go of the past before u can have a future with a different marriage.

I just don't understand

I have cried, cried and cried 

It doesn't do any good 

He is cold to my feelings, he talks to his x step daughter four to five times a week

He talks more about his x step child more than his own real kids 

I am very hurt over this 

Idk what to do