Hello ! I totally understand your fear. And I do agree that you should talk with your therapist about ALL your fears and thoughts about his going to law school because it IS going to be a huge change for you and you WILL be alone a good share of the time.

So make sure you tell the therapist everything that you're afraid of.
Do you have any friends that you could get together with occasionally? Perhaps in time you could start a group of "hopeful lawyer" wives and get together a couple of times a week.
I wish you the very best and I hope you keep us posted as to what happens. God bless and please take care. Hugs, Lee