Ok, so first question: How often do you WANT to fuck? And how often CAN you fuck? No, seriously, these need to be answered first.
For me, old and fat, I can only really perform a max of once every 2-3 days. And I really want to get laid about once a week. It's a combination of factors like Sugar budget, libido, non-BCD activity schedules, etc. Accordingly, I try to schedule one BCD date a week, spread across my SB's according to the frequency commitment I made as part of our arrangement. For my A-list SB's, I generally set an expectation of 2-3 meets a month, then in practice, I schedule each SB every two weeks, and I alternate between my top two SB's. For my double the allowance Porn Star SB's I set an expectation of once every 4-6 weeks. Then I weave them in during the occasional gap in my A-List schedule. For my B-List SB's, it's "schedule from time to time" - maybe once every 2-3 months - when I am available.
If my budget and libido were much higher, I'd schedule each group more often, of course.
Next, once I establish a frequency I know I can maintain, I tell all my SB's that I have a flexible schedule - as long as I schedule at least one week out. This gives me the option to decline any last-minute BCD requests without violating my agreements.
About the appearance of exclusivity, I also subscribe to the "don't ask, don't tell" philosophy. In negotiating the agreement, I make it clear that I have no expectation that she will be exclusive if she chooses to see others. I make this discussion about her, and how I will never be that "controlling asshole" type she has dated in the past. I tell her what she does and who she sees when we are not together is her business and she does not need to tell me about it unless she wants to. I only ask her to take appropriate steps to ensure that we will be "safe" (to have BB sex) the next time we meet. Now the unstated implication here is that all these concepts apply to me as well. But I never actually say that. I want to make her comfortable that our arrangement will not infringe on her life or time beyond our scheduled dates.
If at some point she asks me if I am seeing anybody else, I really don't want to lie - it never ends well. But that doesn't mean I tell her everything. I make a judgement call at the time about what she wants to hear. But when this has happened (infrequently) she has usually been hoping that I am not regularly seeing someone else. So I may get a little "creative" in how I truthfully answer: "I am not seeing anyone else - right now." In my mind I am being rather dynamic in my definition of the term "right now." "Right now" could be within the last 24 - 72 hours, or it could be withing the last month, etc. So saying "No, I am not seeing anyone else right now" is the truth within the scope I define. If she really pushes back and asks for specifics on other partners, I will tell her, of course. But so far, that has only backfired on me one time. She had told me she's ok with me seeing other SB's, then when she found out I had seen two girls 2 months prior, she went ballistic. It took a few days for her to calm down and reconcile her feelings.
Note: There are others here, especially our own Papa Sweet, who don't agree with this approach. They will always be upfront about the number of partners they are seeing, or at least that the number is greater than zero. I will defer to those in the tell-all camp to chip in....
Life is good
The Cat