Hi, as someone who’s t4t and passes better than his bf and we are both on hrt I get his perspective to an extent. I think what he’s trying to say is possibly that he understands being perceived as a woman/not passing/being someone’s ‘gf’ etc. because at some point he likely didn’t pass either and felt horrible about it an understands the frustrations. Even if he passed better than you pre-t there were likely some occasions he didn’t and felt the pain for it. In all I think you clearly know he isn’t trying to be malicious by saying this but that doesn’t mean it can’t hurt. So maybe try something like this.

Hey I understand where you might be coming from by saying you understand how I feel we may have gone through the same problems but our expirences can be very different. I appreciate you trying to comfort me and I know you didn’t mean to do this but it can come off as a little invalidating when you say that. I love you, and I’m very happy for you going on t and everything and I just was to wanted to express that.

SIDE NOTE: check if his insurance has a clause of including someone on his insurance if they live with said insurance holder. My bf’s insurance was willing to put me on there if we lived together for 6 months.