It's never really bothered me either. However, i can certainly understand how it could.

It's not a selfish thing to want this relationship all to yourself. I think it's a normal phase to grow into and eventually, out of.

I do think that you could ask your therapist not to talk about other patients with you. I can not think of a single time my therapist has mentioned it, unless I have specifically asked about it. Tell him how it makes you feel.

Listen and try to hear what he has to say.