Is it normal to lose all interest in socialization after a long relationship ends?

As a teenager I was a pretty normal person with regards to how I acted around people, but my true personality is very weird and I learned from a young age I had to act normal to be liked. I had some friends, had relationships with girls, but I never really showed my true self to anyone and put on a facade to make myself liked. Then when I was 19 I met a girl who was literally a female version of myself. She was the first and only person who really loved me for who I was, I no longer needed to change my personality to seem more normal. She loved me for who I was and not for who I pretended to be. So I stopped talking to everyone, since meeting her all my past friendships seemed pointless and all I needed was her. We were together 5 years, I'll spare you the whole boring story but ultimately the relationship was destroyed by extreme neuroticism on both of our parts.

Since then I've lost all desire to socialize and live in general. I'm not suicidal. I just can't go back to putting on a facade to make normal people like me again, it just feels pointless. It's been 6 years since we broke up. I'm not still reeling over losing her. But any desire to put myself back out there is gone. The chances of meeting someone like her again are too small to go back to how I was before. I'm not sad about it, I'm just indifferent towards everyone and everything. I thought maybe once enough time had passed and I was over her, my desire to be social and live life would go back to how it was. Well, the sadness over losing her took around a year to disappate but even now, 6 years later the indifference never got better.