Friends that you had to let go.
I've basically let go all of my friends at those point. Most of them I met through playing music. If you're a musician you probably know drinking is pretty common. At least with the genre I played. After my younger brother passed, I gave up drinking. Most of my friends were drunks. I couldn't take being around it anymore.
I'm 45, married with 4 kids. Most of my friends are in their early 40s, single, no kids, no responsibility. Once I stopped drinking we had nothing to talk about.