She may be your friend, but at this point in your lives she may not be your playmate. I have both and they aren't always the same role in the same person all the time.
It doesn't sound like she has kids????? You said she's busy with her business. What do you guys have in common - schedules, family, events???? That may be part of it.
I noticed after I had kids that there are lots of women out there (some with and some without kids) who needs confirmed plans that don't tend to change. Well, I can't really operate that way. Stuff comes up. So, we drift apart. But then as lives calm down we can drift back together.
It sounds like you're drifting apart.
When people start talking about 'ending a friendship' - I guess I don't really know what that means. Just because you guys are growing apart doesn't mean she can't still be your friend in a cycle of another couple years when things have evened out for you both... does it?
However, the relationship shouldn't hurt and confuse you. What I would do is get other friends. Let her see what a great time YOU are having. People always gravitate toward other people who are happy about their place in life. So, rather than confront her..... just develop a life that makes you happy and let her decide if she wants to be in it with you.
maybe that would work?