Day 169: is my drummer cheating on me?

Today my drummer (Ben) called to say he'd been asked to play drums for another band. Which is fine. I think. Ben and I have played in various bands together since we were 13 years old. He's not the only drummer I've ever played with, but he is the only drummer I've ever had in my bands (as in projects I've originated and really care about). So knowing he's going off to play with another crew definitely feels like a wrench of sorts. But at the same time, I don't feel like it's a wrong thing for him to do. In fact I kind of feel like it's a good thing for him to do. But I still feel weird. Does it matter if a drummer plays in more than one band? Can a band member divide their attention between two bands or does it spell the beginning of the end for one of them? My first thought is that it's fine to be in different bands. I guess it only gets difficult when commitments for either group clash. Then one has to be prioritised over the other. One has to be chosen as more important than the other. One becomes the wife, the other a sometimes mistress. But, as we currently don't actually have a band, only a two person computer project, Ben actually isn't playing in any band at all right now. Will his starting to play in someone else's, mean our new band never gets born? We can only wait and see.