It might appear that manipulative people spend a great deal of time engineering opportunities, but the truth is that many of them are simply good at capitalizing on them. While they do seem able to spend a little time setting up their partner, most of their abilities are centered on being able to make the most of any event that will leave them with a greater share of control within the relationship. Small incidents will take on a larger meaning around this type of person, so a relationship with them can quickly turn into a minefield if their partner is not good at recognizing a manipulator.
Maintaining a relationship with another person is about accommodating their needs at times, and those who want a successful relationship are often willing to do it whenever possible. A person who is intent on being in control will use this fact to gain the upper hand, and they often do it in a way that appears innocent. They will find a way to take advantage of any incident where they look good to others, and they will mention it in front of people they know to get the other person to agree they are wonderful.
They might have requested their partner to pick something up at the market for them when they know it is expensive, but they might insist they need it. When they suddenly appear at the check-out with the extra cash needed, they will then use that incident to point out how nice they are to friends and family. They will conveniently leave out the fact they knowingly requested the purchase when the other person did not have the money, and they realize they are forcing their partner to agree with them in front of others to make them look good.
This is a prime example of manipulation, and it is something that happens in many relationships. By the time a person is fed up enough to leave, their friends and family might think there is something wrong with them for ending the relationship. Leaving as soon as the person recognizes this type of behavior is best if they want a good partner who will treat them well for the rest of their life.