Boys say it's only a matter of time before people are always abandoned, without exception. What do you mean?

In fact, this sentence means that all people will eventually be separated by others. It's only a matter of time. All people are like this, no one is an exception. I don't think that's necessarily the case. In feelings, some people will always like each other, and the person they have always liked will not be abandoned by others, because he has always been the person others want. How could he be willing to leave him