Losing the desire to share can mean a variety of situations, and here are some possible explanations:
Affection dilution: Whether it's a guy or a girl, when their feelings for someone start to fade, they may share less with the other person. The diminished desire to share may be a natural reaction because we are no longer as interested in each other's things as we used to be.
Busy life: Sometimes, the stress of life and the busyness of work can leave us without the time and energy to share the bits and pieces of life with each other. This does not necessarily mean a dilution of feelings, but only a stage of life.
Lack of common interests: If there is a lack of common interests between boys and girls, it can lead to not having much to talk about with each other. This can lead to boredom and alienation on both sides.
Trust issues: If there is a trust issue between both parties, it can lead to a reluctance to share too many things with each other. This may be because of a fear that the other person will misunderstand their intentions, or because of past experiences that have led to a sense of distrust in the other person.
Personal personality: Some people are naturally introverted or independent and may be reluctant to share too many things with others. This doesn't necessarily mean that they don't care about each other, but it's just a manifestation of their personal character.
In general, the loss of desire to share can mean a variety of situations, and the specific reasons need to be analyzed on a case-by-case basis depending on the circumstances of both parties. Both boys and girls should pay attention to their emotional communication with each other and try to figure out how to solve the problem.