If you don't hear from someone, it's probably not because they are busy; they probably just don't care about you that much
When we make strong connections with people, we go through phases where we are always in touch with that person while other times we hardly hear from them. When a close friend or significant other distances themselves from you, there's always the chance that they have a legitimate reason why. Perhaps they are going through a tough period in their lives or work has been keeping them busy. Other times, it's just a sign that the friendship/relationship has run its course, and you are simply growing apart.
via Psychology Today
Statistically speaking, most people that you welcome into your life are only temporary; only a select few end up staying. If you're searching for answers as to why this happens, the answers are endless. We all go through periods of our lives where we have to give different people/things our priority. Chances are, if that person really cares about you, they'll make an effort to stay in touch.
For those people who come into your life and just as quickly disappear, the truth is most likely this: they don't care enough to stay in contact. Their happiness and fullfilment doesn't depend on you and thus don't feel the need to keep in touch.
If someone in your life has recently disappeared into thin air, this is probably what you should take from it: they care about you, but only when it is convenient for them. If you are constantly asking to spend time with them, but they always come up with an excuse as to why they can't, and then last-minute say they can, you're probably just their backup plan.
So what can we do when we feel like someone is just treating us like we're their 4th or 5th option? Sometimes we just need to accept that not everyone that enters our lives stays. This doesn't mean you can't still be friends with your high school buddy after he or she moves away to college. If they care about you, they will put in the effort to keep in touch. The important thing is to make sure we are not staying friends or in a relationship with someone who doesn't treat us the way we deserve. That's when you know to let them go. You don't want to waste your time on a person that doesn't care enough to stay in contact.
