kitkat...welcome to A2K

And thank you for giving us this opportunity to listen and hopefully be of some help to you.
The whole idea as you stated in your post about going to some individual sessions alone with the therapist were to be able to get things off of your chests. Obviously things that you neither feel completely comfortable talking about in front of the other person. That said, when he came home from his session, you should have never asked him anything! Especially not asked him to elaborate on anything they talked about. That was between HIM and the THERAPIST. Period, end of discussion. You will also have your turn with some individual time with the therapist and by the same token, your man should grant you your privacy about what the two of you talk about in session.
As much as you say you were not trying to pry, you were doing just that, I'm sorry to say. A more supportive approach would have been you saying "How did things go?" and when he said , "Fine". JUST drop it. If and when he feels comfortable communicating with you, he will. This was ONLY his first session. And please trust me when I tell you, if he continues to go to sessions on his own and you continue to try not to "pry", but ask him to tell you about it, he WILL eventually stop going because he will feel his own privacy and boundaries are not respected by you.
Be thankful that he is going to therapy at all. He obviously wants to make this work between the two of you. Let him know that you are grateful for that, but don't, don't, don't ask him any questions about HIS time with your therapist.
Keep your lips sealed, give him a kiss and tell him thank you for caring so much about the two of you.....