I'm the opposite. I find it uplifting to think of my T having a good full schedule of other clients - I suspect because that creates a kind of diluting effect, and therefore less pressure. And some of them are bound to be as irritating as I can be

If I fantasized I was the only client I'd panic a bit. That being said, I would not wish to discuss therapy with the ex-lover who recommended my T to me. That would be weird.
I'm in touch with my T a lot via calls and texts and emails. It is really helping me and I think I'm growing emotionally with her nurturing-ness, but I get little stabs of guilt and doubt. A way I can justify this in my own head sometimes is to think 'this must be normal for how she works, I bet all her other clients are doing the same (or at least half of them, anyway) so it doesn't mean I'm abnormally needy to do this'.