I would simply propose that it works far better for the SD to say something like:
“I like you a lot and enjoy the time we spend together. I would very much like to continue seeing you.”
“I have to admit, though, that I’m getting the sense that this isn’t working very well for you right now. And, because of all of the schedule uncertainty, it’s not working all that well for me, either. I’d like to take a break and let you decide whether you want to continue this arrangement with me or not.”
“Please don’t reply right now. I’ll wait to hear from you after you’ve had some time to think it over.”
Then you smile, wish them all the very best and tell them that you hope to see them again if they decide that is what they want. And then walk away with no hard feelings and the expectation that you’ll never see them again.
Or some version of the above.
In my experience, if the woman wants out she’ll take this opportunity and run. But many times, this doesn’t just leave the door open for her return. It tends to make her want to return. In some cases, it can make her want to jump your bones right there. That can be just a great goodbye. Or it can be something else. You never know. And that is part of the fun, I think.