Manipulation is a tool for trying to get what you want through the control of somebody else. More often than not, the other person is somehow shortchanged in the process. Over the course of time, when one person continually manipulates the other, resentment builds. This resentment often results in many behaviors countering the attempts at manipulation; examples being leaving, withdrawing, fighting, counter-manipulation, etc. None of these behaviors are good for any of the parties. The situation becomes lose-lose.
But such long term results are the farthest from anybody’s mind when it all started. Perhaps they were a young couple infatuated with each other. One, either intentionally or accidentally, discovers that manipulation works with respect to the other. They can get what they want rather effortlessly. They did something, they got a reward, so they will likely do it again for a reward. This is basic behaviorism psychology. Again and again this happens, often without a deliberate decision to do so. However, the more they do it, the more difficult it becomes to be successful. They descend into a behavioral rut, so the natural response when in a rut is to double down. This maybe kind of / sort of works, but the consequences mentioned in the first paragraph will probably be starting to manifest themselves. Not good.
Since men typically tend to be more direct, and women indirect in their styles, manipulation is more of an issue with respect to them. So it is something that they should always be on the watch for. And if they see it in themselves, they should stop. For their own sake, as well as for the sake of others.