When should I tell my boyfriend i stutter?

When should I tell my boyfriend i stutter? I’ve been dating this guy for a year and he still doesn’t know I shutter. I’m not comfortable with letting him know but I feel like I have to since we both want to be with each other. In addition, he’s asked me if I wanted kids in the future and I said no, my excuse was I hate them but I’m scared my kids are going to stutter. We just got into an heated conversation about something. I kept trying to say my position and when I got to a certain point, he would interrupt me and I’d have to start all over again (this wasn’t a stutter though). It happened 3x. He then said he doesn’t know if I have a stuttering problem or I get side tracked. When he said it, it made me aware of the fact that I had to tell him and it bummed my mood. I don’t know what to do. Edit: I’ve just told him and he was super understanding about it and he said it doesn’t bother him.