Sounds like an emotional block to me. No one is "fated" to be alone. Being alone is a choice, I believe.

There are many variables that effect how large or small our social network grows into. And, social networks are not stagnant. They grow and they decrease over time as we change and the people inside those networks change. The variables that can effect our social networks expand far beyond us and our needs to: our workplace, where we volunteer, go to church, shop, eat out, go to school, community sports, vacation, go to the doctor's office, who we are already friends with or no longer friends with, etc.,.

Ten years for me now with no active social network and that's because I've made zero effort to activate mine again by going to Meetups like I did before, which kick started my social circle and what I used to grow my social network with. But, like with everything, it fizzled out when I made some life changes and stopped participating in my Meetup groups, so people stopped reaching out to contact me. The friendships I nurtured from those Meetup groups grew to where I didn't have to rely on Meetup events to see these people, but we all just stopped reciprocating communication invites with each other. It happens.

Ending this friendship is painful for you which is normal. No one can give you step by step instructions how to heal. All we can do is give you suggestions, talk about our personal experiences with ending friendships.

You will feel better about losing this friendship with time. What's that cliche? Time heals all wounds. It's true as cliche as it is.