Grand parent visitstion

My name is Marlene turner, I would like visitation to see and grow with my grand children, but the mother wants to be with me at all times because she doesn’t want the father around them. I only want the best interest for the kids a relationship between me and them nothing more. I want to be grandma, but being caught in the middle of a bitter fight between the mother and my son. I just want to be with my grand children for I love them so much they have my heart, but the mother wants to be with us at all times. I don’t need to be watched over she knows that but I just want my time with them. She’s having a trust issue that the kids will be around their dad. Which she keeps them hostage that he can’t make contact with them. I need help please!