I would also gently suggest that it’s possible that your feelings about this have more to do with your anxiety than with his stutter. There are many, many things outside of your control when you have kids, and your children will all have something that’s hard for them because life is hard. Stuttering is one of many, many things your kids might struggle with and it’s honestly not close to the worst thing. My husband’s bio mom is an addict and I’d hate for our kids to end up in her situation, but I wouldn’t not have kids with him because of the possibility they’d inherit a propensity towards addiction. He’s a great guy and has a good life (which it sounds like it’s also true of your boyfriend), so why would I worry about our kids possibly stuttering?