I don't want to share my babysitter

I'm not sure if it's just a NYC thing or a universal truth, but finding a good, reliable babysitter is a PAIN in the ass. It takes research, phone calls, emails, and in my case, a little bit of luck. I met one of my amazing nighttime baby sitters (not my daughter's nanny but a woman we use in the evenings) outside of my building one day last summer. I was with L and the woman came up to me and asked if I ever needed a babysitter. Long story, short: she's amazing and lives one floor below us. Awesome. And, now we use her whenever we make the rare venture out in the evenings for an adult-only event/dinner/movie, etc. I'm sure my nanny would love the extra money, but unfortunately on top of her hourly fee, we also have to pay for her cabs to and from the train station. So, that's just not going to happen.

Well, the other day, I was on a group email with some of my mommy friends (women I met through a mommy stroll-in group when I was on maternity leave) and one of them asked if anyone knew of a good babysitter for evenings during the week and/or weekends. Part of me wanted to reply to her and share my amazing luck...and part of me, well, didn't. What if she started using her regularly and then when I wanted to use her, she wasn't available?? I have a deal with another mommy friend (who I turned on to this sitter as well) that we check with each other whenever we book her. So far, it's worked out really well. But to add someone else to the mix, well, you know what they say...two is company and three is...well...I just don't want to risk it.

Am I being selfish? Should I just share my good fortune and hope that my babysitting karma benefits from this act of selflessness.

It's been a week, and I still haven't responded to her email. As far as I know, no one else did either. So, maybe I'm not the only one who wants to keep their sitter all to themselves...