I’ve been in my relationship for a year & a half. I didn’t bring up my stutter until around the 7-8 month mark because it’s one of my biggest insecurities (maybe it’s the same for your boyfriend?) so just give him time, it’s a soft spot. I would say don’t finish his sentences for him, it kinda makes (SOME) of us feel worse about it. Whenever he does come around to talking about it suggest those things such as speech therapy. Until then I honestly would say just keep doing what you’re doing. It’s a internal battle. (Im not the best advice giver, I’m just going off personal experiences) I’m praying everything goes well for you two!