Your partner can be closing down the lines of communication overtly or covertly. Direct or overt refusals to engage in discussions, such as "I don't want to talk about it" often contain an implicit threat to leave, get angry or punish the partner attempting to initiate the conversation. The situation can become more volatile or intractable, and depends on the personality and stance of the partners.
The person that refuses to talk can be motivated by the fear that if a purposeful conversation doesn't occur, distance and disconnection will occur and will jeopardize the foundation of the relationship, potentially destabilizing it and putting its survivability at risk. It's not unusual for one partner in the relationship to be more acutely aware and sensitive to a loss of freedom and personal power, and the other to be more concerned about and stability of the relationship.