A friend once said to me, about her ex, "I married him because I knew he would never leave me. I didn't realize he would follow me into the bathroom."
He followed her everywhere. If he couldn't be there in person, he would call frequently. When she left the room, he wanted to know where she was going. If she left the house, he wanted to know why, where she was going, and when she would be back. He always sat right next to her, and was always touching her. Her neck was always covered in bite marks.
This was back in the days before everybody got tattoos, but, if that had been the fashion then, he would have wanted her to have his name tattooed on her somewhere. In plain sight, no doubt.
It's ownership, girls. He is telling the world you belong to him. And, because you belong to him, he feels he has a right to know where you are at all times; who you are with, when you will be back.
This is abuse.