What I’ll say is always be on his team. And always give him the respect you know he deserves, people who trust you will follow in your lead of having patience with his delivery without necessarily feeling empathetic. The thing about us stutterers that I’ve realized, is that a lot of us tend to be pretty intelligent. A lot of that comes from opting to listen more than we talk. And when we talk, is to say something valuable or additive to the bigger conversation. You know your bf and you know how valuable his words are. Initially in some social settings you should become a bit of the ‘validator’ of his value. For me, that was my mom and my sisters when I was a lot younger. They’ll openly ask for my opinion on things, regardless of who was around. Because I wasn’t always willing to talk/share, I made sure I always said something meaningful/helpful even though I stuttered. Now I’m 30 and while I’m still not the most chatty person, this stuttering doesn’t stop anything I want/have to say. So differ to him and his opinions, especially if he has good/unique takes to things. It grows confidence and trust from people around the both of you. Overtime you’ll see he’ll become more confident because he knows that people trusts his words regardless of the delivery. Good luck.