You are rightfully offended, as this is an objectively offensive comment, especially coming from a professional, assuming, of course, that your bf didn't make it up.

But I wouldn't focus so much on what's happening in his therapy. His therapy and whatever happens there is his business. I think, it's more important to focus on not letting things like that undo all the work you have done on yourself. Keep your focus on yourself, not on who said what about you if this is a third party you have no contact with and who is not a part of your life.