If you are indeed infected with HSV 1, and have never had any oral or genital sores, we really don't know how to reduce transmission effectively.

If you had this genitally, it will be given off from your body rarely and is unlikely to be transmitted through intercourse.  if you have it orally, you can transmit this via kissing or giving oral sex but without symptoms, we can't judge how likely this is to happen.  Giving off the virus, shedding, is less likely in people who are asymptomatic, but we know it can happen. 

How long have you been together?  

The other thing is that the IgG test misses 35% of HSV 1 infections, compared to the gold standard western blot so it is possible that your partner's HSV 1 infection was missed.

About 50% of US adults have HSV 1 infection.

Terri

I believe I was infected by my ex-wife, who  got cold sores on her lip and said she got them from her mother, who also got them. We were married from 2006-2021. It's entirely possible that I got it after, but this seems the most likely situation.
I had a partner for 14 months since then, and she tested negative for HSV1 after the relationship ended. 14 months, fairly active sexually, and she's negative - we did not use condoms. 
I have been with my current partner for two months, and it is a long-distance relationship. We see each other quite infrequently. (She is amazing and worth the sacrifices of this kind of relationship - I try to be). She tested negative prior to our relationship.
I know that numbers are difficult with this, but I'm really trying to wrap my head around the chances of transmission. She is a cautious person about these things, and she is worried about getting an active case and potentially passing it to her children through shared drinks, kisses, etc. 
I am assuming that kissing is our riskiest chance for transmission. And we're not giving that up! In terms of oral sex, how much of a chance of transmission is there? 
We are using condoms for intercourse, but neither of us is super happy with that. But if that makes her comfortable, I'll not complain. That said, when you say that transmission through intercourse is unlikely, what does that mean? And how much might an antiviral like Valtrex help reduce that possibility?

Thanks so much for your time and help with this.

We don't have data on any of the questions you are asking.  But I can tell you that I've never seen transmission of HSV 1 through intercourse, but it has been documented.  for genital HSV 1, once you've been infected for two years, you shed virus on about 4 days out of a year.  We are less clear about HSV 1 orally but almost certainly you shed virus more often if the infection is oral as that is the preferred site for HSV 1 to live.  

We know that Valtrex reduces transmission of HSV 2 by about 48% and shedding by about 70% but we don't have the same numbers for HSV 1.  However, if I were you, I would take it daily for the chance that it might reduce transmission.  

I get cold sores and have taken valtrex daily for 20 years and have not had a full blown cold sore since, and was getting them about four times a year prior to medication.

The truth here is that there is going to be some unknown risk to her.  and if she gets it, she is unlikely to pass it to her children through normal family situations - avoiding kissing them on the mouth would be a good idea if she does get it and many people don't do that anyway.  

If she isn't with you anymore because of this, then there is better than a 50-50 chance that the next person she dates will have HSV 1, most don't know and the test misses 35% so there your are!

Terri

All sound right?

She isn't going to break up with me over this. We're just trying to be as safe as possible. She asked me to thank you for all your time and expertise. I thank you, too.

Terri