In most relationships, the partners have an equal say in all important matters. Many people sit down and define what is important, and this keeps both people in the loop. It is a good way to conduct a relationship. Both partners agree before decisions are made who will make them, and they also decide when decisions must be discussed before being made. It is an equitable way for each person to have a say in the lifestyle they live.
There are people who want to control their partners completely. They believe they have the right to make any and all decisions, and their partner must agree to them. There are several ways this is done. Manipulation is one way a controlling partner achieves their goal, and sometimes the other person does not even recognize it. Guilt has often been a lever of control in relationships, and the controlling partner carefully chooses an incident where they can attack their partner's decision making abilities. Over time, these actions bring their significant other under their full control.