1. What two or more (or less) consenting adults do is no one's business- let alone T.
2. I find it weird that a T would be against couple therapy.
3. I'd terminate her the minute she said you're not fit to be a parent- that's a cruel judgment (doesn't matter whether or not you want kids).
You really don't need another person judging you- you are already being too harsh on yourself.

Also I don't understand why she sent the letter to your doc too...