No Alice either but since you've posted it here...

F didn't know you and his T have this phone session beforehand? Not OK- I too would feel betrayed had my T talk to my family behind my back (and would immediately stop seeing my T). The T shouldn't agree to such "session". Telling him afterwards yeah, it's at least stg but still too little too late .
I think you're too involved in your partner's therapy- it's not yours it's his (was great of you that you helped him search for a T but that should be it). If you two want to deal with stg together you can either go with him to his session (or he could go to yours) or find a MT.
Hate this whole concept of going behind one's back. Keeping secrets not that good for a RS.