My experience isn't quite like yours, in that I was still seeing my marriage counselor when I started with my current T about 8 months ago. But I was seeing him in part to deal with that relationship, the transference and attachment, which ex-T hadn't really helped me with. I was concerned when I learned (just before our first session) that T used to work with MC--was afraid it would make him be biased toward MC. I will say, in the beginning, T seemed a bit skeptical of some of what I was saying about MC.

But then while seeing T, ex-MC and I had a major rupture that ultimately led to the end of our therapeutic relationship. At first, T seemed to understand why MC reacted the way he did, which was difficult. But then, as I talked to him more about it--and also told him what I needed right then (support, not seeing MC's perspective)--T seemed to understand my side of things. And ultimately became very supportive (and actually fairly critical of ex-MC). It took a little time though--it's like we had to build up trust on either side, if that makes sense. Like, he'd known MC for 15 years, so it made sense that he wouldn't immediately accept negative things a brand new client was saying about him. But then...the more I shared things with him (including some e-mails from MC), it's like he started to get it. And now he seems very much in my corner. He's not perfect, but when he does mess up (hurts or offends me), he's very open to feedback and willing to admit fault, which is basically the opposite of MC.

So I'd suggest, if this new T seems to have some potential, to give her (him?) some time. If you've trusted one T for so long, then got hurt, it can be really difficult to start trusting a different one. I'm really glad I stuck it out with T after a somewhat rocky first month or so. He seems like a completely different therapist to me now, nearly 8 months later, than he did on, say, day 30.