Aspie with social anxiety disorder here. I think you need to toughen up regardless, because if you intend to stay together there's no doubt your combined "downs" could be pretty bad.

That said, I feel learning to share your emotions and how to explain/express them is pretty vital in and off itself for pretty much this exact reason. Communication is key to any serious relationship. If your boyfriend is refusing to express them to you, then he needs to find someone he can because otherwise he basically stunting himself in my opinion. Based on what you've said it already sounds like he should talk to a therapist. But at some point that does need to include you. It's pretty hard to have a relationship when you can't talk to each other.

As for you not keeping it real, does he have a legitimate basis for that? Even if you're telling white lies he can see through, I'd have to take his side on that part. Communication needs to be open and honest, even if hard to hear. If he's just saying the phrase, then that's obnoxious.