Don can't handle the thought of Sylvia--available--as a legitimate prospect to be in his life on a regular basis so he tried to control her completely so he could remain in his comfort zone. The thought of a free Sylvia scared him to death. He's not good at marriage and he knows it.
Don did treat another woman like that--Bobbie Barrett in season 2. He left her cuffed to the bed for the staff to find half naked when she talked about women calling him "the Don Draper treatment" sexually. She was taking control and he didn't want that. It scared him shitless. Remember Don being flabbergasted when Bobbie left one of their encounters early because she had to go see her college aged son in a play? Don couldn't comprehend that this agressively sexy woman could also be a caring mother even though she acted like a "whore/prostitute" behind closed doors. It didn't compute with the good woman/bad woman image Don has stuck in his mind.
Dr. Faye (whom he dumped to marry Megan) had Don pegged. He's only interested in the beginning of things. He can't maintain a healthy intimate relationship. Faye was an intelligent woman whom he enjoyed being with; she challenged him.....and he dumped Faye for the image of saintly Megan who was comfortable around children when Faye wasn't. Don couldn't handle a divorced Sylvia who's more healthy than him psychologically. She'd find out what a scared little boy he still is on the inside. Rachel figured that out. Sylvia would have as well.