I love this post. I am a man who has been accused of being manipulative by the way. Other adjectives that come to mind are controlling, self serving and selfish. Manipulative people, such as myself, manipulate for good i.e. To save money, to get ahead, to raise healthy smart kids. The key is the purpose for which someone is manipulating and, by your post, you acknowledge that your mate does it for good or what he perceives to be good. So, unlike my wife, do not condemn the manipulative man if his purpose is for good; rather, manipulate a situation exclusively (without him) if you wish and recognize that he is who he is and you are who you are. Do not confuse manipulation with him trying to control you - he is trying to get ahead or do something that benefits him or you or both of you. My opinion. Now, if you think he is manipulative for an evil purpose or selfish purpose, ask whether there is any benefit to anyone except him. I guarantee that there is, namely you, and I guarantee that his intent is not only to benefit him but to benefit you also.
An example: my wife has no formal education; she grew up in Italy and takes great pride in cooking, cleaning and laundry. So when it comes time to buy a car, she would walk into a dealership and pay the MSRP. I would not. And because I do what I do - research, negotiate, et cetera - her claim is that I am controlling and manipulative. And while it is true that I am controlling and manipulative in the above example, my intent is not evil but rather to benefit us, namely, not to get screwed by a car dealer. She does not understand this. And round and round and round we go, her claiming that I am manipulative and controlling and selfish and me trying to explain that my actions are in the best interest of our family. I hope this insight helps you. Thoughts?