I have a friend from secondary school. Once we were very close. She emigrated in our early 20s and would go through periods of intense communication then periods (months or years) of no contact.
She came back to the UK five years ago. We rekindled our friendship but it quickly became clear that I'd gone in a different direction and she was still living the life she had when we were much, much younger.
I planned to gently let the relationship slide them a Very Bad Thing happened in her life. I had to be there after that as she needed everybody around her.
A year or so later I backed off gently when I was sure she was in a better place and had an appropriate support network. We still messaged regularly.
Friend just did a disappearing act again for the past six months (I messaged, no replies), then popped back into my inbox recently.
I don't have the energy for this (her life is always very intense) and would rather let the relationship slide. So far, I haven't replied but I don't know whether to explain, ghost or just carry on.
I'm sorry if the details are a bit patchy, I wouldn't want to out her.
YABU: You're a meany, forgive and move on
YANBU: It's come to a natural end, leave it already