My in laws absolutely hate me

Morgan
My husband and I have been together since I was 18. 7 years. It's expected to go through rough times. The relationship started out immature But together we have grown into adults and live a happy life together. The only issue is his family absolutely hates me. He had a child outside of our relationship and I made the decision as an adult to forgive my husband because up until the point that he cheated he never gave me reason not to trust him. I believe the woman he cheated on me with took advantage of a bad time in our relationship. I do place most of the blame on my husband (this happened before he was my husband we were just dating) but he is a good man and I know that people make mistakes. When we fixed things I cleaned out decorated and bought all the necessities for a baby room to welcome this child into my life. However the mother of the child has made it clear she does not want me to help raise this child, she even went so far as to take a tpo out on me claiming BECAUSE I have a room in my home for her child she believes I might kidnap him. My husband and I have decided to not press for custody because this woman is going to make life a living hell for us and that child if we get any kind of custody. I truly believe she would go as far as to tell the law I abuse or molest her baby if we ever were to have him. She can do some real damage and ruin my career and my life. I want a family of my own and I can just see police and cps at my door every day if we were to have custody. This is not a decision I made myself this decision was made between my husband and I before we even got married. His family has never liked me because they think I am "stuck up" and believe I've lived a prove ledger life which is far from the case. I grew up in an absuive alcoholic home and it was not easy. My mother worked her ass off to buy things and to put up a front to make our home seem happy. Well I had a crazy out of no where argument with his sister today. She called me cursing about how I've ruined his life and I'm not family I'm just his wife I'm not blood. That I am keeping the whole family from being able to see the child (the woman is still legally married so legally it isn't my husbands child until proven so with dna). It kills me to be blamed for this and I am worried that my husband is not being a father because of me. He says that this is his decision and that's how he wants it to be but it still hurts to have his family blame me for "breaking up the family" "ruining his life" and "keeping his son from being able to be a part of the family" his family has never liked me like I said but I have continued to go out of my way for them. We spent $4,000 for his family to be able to come down to the beach for our wedding. Paid for everything. It blows my mind because his family is crazy. His sister has 3 kids by 3 different men and she's constantly bringing men in and out of her kids lives. His mom is completely dedicated to his dad who treats her like shit. He divorced her years ago and only calls her when he needs something. He has multiple girlfriends but he pays for my husbands moms house and it's really a wreck. Like some dr. Phil shit. I just don't know what to do. I get angry with my husband because of them! I don't know what more we can do. My husband has told them to treat me with respect and that he chose not to go after custody not me but they still think I'm this horrible person. Even after forgiving their son and bringing him back into my life. I've endured a lot in the 7 years we've been together and they don't see that. They would rather him be with the still married 33 year old woman with 3 children with her legal husband who after a month with my husband quit her job expecting him to support them all. 
Anyone have any advice on how to deal with or how to come to terms with the fact that you will never be welcomed in your husbands family?