Just a vague idea here, that I would like to have story in addition to the sex.
Jessie is heading home from her job at the local cafe. He has been watching her for awhile and wants her. He's a bit on the rough side and as she passes by the alley he's hiding in, he grabs her and pulls her inside, drugging her with chloroform.
She awakes locked, naked in a room aside from a collar thats been locked around her throat. He breaks her will, quite easily as she fears him. Over time, she learns to depend on him for everything. He loves the idea of her breasts becoming engorged with milk but doesn't want her pregnant so he gives her drugs mixed with her food that both prevents her from getting pregnant and makes her produce milk. Along with his stimulation, within a week after he takes her she begins lactating. He makes it purely a sexual thing.
Over time, she falls for him and he has her so rewired, he starts taking her out of the house with him. Does she reach out for help? Or is she his little toy forever?