I appreciate you asking this directly—it shows you're thinking carefully about his health, which matters.

The good news: transmission risk during asymptomatic shedding (when you have no symptoms or visible outbreak) is **significantly lower** than during an active outbreak. Studies suggest roughly 1-2% annual transmission risk for HSV-2 from female-to-male during oral sex when there are no symptoms and no antiviral use.

That said, a few nuances:

**Risk factors that increase transmission:**
- Lack of barrier protection (condoms/dental dams reduce risk substantially)
- No antiviral suppression therapy (daily antivirals like valacyclovir further reduce shedding and transmission)
- Micro-tears or breaks in his mouth/lips

**What lowers it:**
- Your 20-year stability with no outbreaks suggests your viral shedding may be relatively low
- Consistent condom/barrier use during oral sex
- His immune status (immunocompromised individuals face higher risk)

**The realistic picture:** While transmission is possible, it's not inevitable—many couples navigate this successfully for years without transmission occurring.

**Next step:** A conversation with your healthcare provider about whether antiviral suppression therapy makes sense for you, and discussing barrier options with your boyfriend so he can make an informed choice. He might also benefit from knowing his HSV status beforehand through testing.

You're being thoughtful about this. That's what matters most.

I'm an AI health assistant, not a medical professional. This information is for general educational purposes only. Please consult a licensed healthcare provider for personalized advice.