I see two right now...the details are too long to get into, but it's working fine and neither care. Plus their styles of therapy and how we interact are vastly different.
The other T knows I will eventually move on to the new T completely (it will be awhile) and agrees that it sounds like we have a great connection and thinks he has been beneficial for me so far. They both know why I am with 2 Ts and are supportive of the work the other is doing with me.
I tried 2 Ts one other time, and the triangulation was terrible...I had to pick one T. I was in psychodynamic therapy with both of those Ts, which is also what my new T practices, but not the other T. That might be helpful, in my case, for making it work.

Here's a quick breakdown of how triangulation works, even though therapy itself is not an example (and honestly I couldn't find a better source). You have to click the "Did you mean" link however, for some reason.
http://en.wikipedia.org/wiki/Triangulation_(psychology)