My son likes grandma and grandpa better than us.

My 4 year old is always asking to go to grandmas. They live next door and often she will come steal him. Lately he will spend several hours there and she watches him once a week while we work. When she tries to bring him home he has a melt down. Everytime. Tells us he doesn’t want to play with us. And stay at grammas for a long time. I know we are a lot stricter than she is. And often we bump heads with her cause she’s too soft and gives into him when he has tantrums for things. He will have a melt down when I try to bring him home and she will say he can stay but there’s no chance I’m going to reward his behavior. Then gramma sees sad cause he will cry for her for the next hour when we get home. I told her the other day that I think leighton likes them more than us and she made the comment that it’s because she plays with him. That felt like a fellow blow because I’m mostly home with him and the 3 month old. I’m busy. Cleaning, cooking lunches and dinner for husband and my 4 year old. Often he prefers to play the game or watch cartoons and he doesn’t even want to play with me and he tells me he doesn’t love me sometimes. He’s been biting my 3 month old and hitting him this last week. I don’t know what I’m doing wrong. I’m almost tempted to not let him see grandma as much anymore but that’s probably not a good idea because he loves her. Just hurts when he tells me these things. And says he wants to live at grandmas.