I don't know; if you are long-distance I could see it might be hard to bring it up, that he'd started seeing a therapist. "Guess what I did today?" just does not cut it with something so personal and important to one's self. He could be having trouble with who he is and who others are and boundaries, etc. and "giving away" that information might have been hard for him; did you discuss it with him at all, ask him why he did not tell you sooner? If you are not sharing your feelings with him (disappointment that he did not tell you he was in therapy sooner) it does not sound like he is getting very good information from you about you to better know what you like/would like from him. If you leave him without discussing this, I, were I him, would be thinking: "Gee, I share that I'm in therapy and it drove her away even though she said she was glad and told me to get help in the first place. Do what she wants and she leaves me; I cannot win.".