Everyone comes into this world alone. Since birth, family members are there to keep them company. When you grow older, you began to make friends. Be it casual or close friends, they still cannot make up for the main purpose you come to this Earth, which is to start your own family for the next generation. You will definitely came to know a few partners in your entire lifetime. For sure, one of them will eventually be married to you and keep you company for the rest of your life. However, you will eventually be separated from each other by accident, illness or natural death. And at the end of the day, you would still be leaving the world alone.
Sorry to say this, but no one can accompany you forever. All people whom you have met are just part of your life.