When we a my SO got together 2 1/2 years ago, I truly tried so hard to be nice to his child. But after time, he's started to be more disrespectful with no consequences. I have 2 sons of my own and they have grown to have a connection with my SO like a father. They call him dad by choice because their dad isn't around and from the start my SS has had an issue with it, clearly. We've have to explain to him multiple times that my SO has taken responsibility of my children, and that he is okay with them calling him dad.