I think this is very wise. Transition is a huge step, especially if you've only been out dressed a few times in TG-safe venues.
Also, I'm concerned about your therapists' statements. The red flag for me is that she said that she knew you were TS after only a few sessions. I didn't know that therapists could determine this. I also don't know how any therapist can say this until you've had a lot more real life experiences under your belt (enough to have gotten over the novelty) where you and your therapist would have had the opportunity to explore your actual experiences more fully.
Please understand that I'm not making a judgment on whether you are TS or not. Only you can determine this. But it might be worth your while to seek a second opinion sometime in the future while you get the depression under control and you begin going out into the mainstream (alone or just with Angies ... not with TG support groups) on a regular basis? I'm not sure what your work situation is, you do risk your marriage, so you don't want to leave any stones unturned. In the meantime, it will be important to actually go out there (a lot) to see how it feels to be yourself?
I wish you and Angies all the best as you meander through all of this.