It is possible to interview other therapists and put off quitting with the one you have until you have found another one. I do not mean you have to go see the one you have in person again - I personally would not think that a good idea for me, but you could say you needed some space or a break and during the time look for another and then quit or whatever with the one you have - and you would have a support t in place then when you actually told him about quitting. Just another option.