I don't know if I should reconnect with an ex-friend
For some context, there was a pretty big falling out with my high school friend group last year that resulted in me no longer talking to one of my closest friends, let's call her D. While nothing dramatic happened between the two of us, D badly damaged the relationship between herself and my best friend, let's call her M. They'd been friends since 2nd grade, so M was obviously incredibly hurt by this. D and M have since talked things out, but M is no longer talking to her. I also quickly stopped talking to D, out of support for M.
D recently requested to follow me on Instagram, and I've been considering reaching out. I'm not planning on becoming as close as we used to be, but I just want to apologize for how things ended up and leave things between us on good terms. But it feels like I'd be betraying M if I were to talk to her, especially considering how supportive M was while I was arguing with another ex-friend.
Honestly, as I'm typing this out, I'm also wondering if I approached the situation appropriately in the first place. D and I were pretty close, and we never directly fought. Was it wrong for me to just stop talking to her like that? Would it be a good idea to reach out? I've been thinking about this for a bit now, so any advice would be super appreciated.