1. Why did I not get a cold sore on my mouth since I had kissed my previous boyfriend and HSV1 prefers the mouth?
In my experience, I more often see women who receive oral sex getting it only genitally, but not orally, even though kissing happened also. I have seen it in both locations, of course, but more often, only genitally. I think the genital tissue and the usually rather prolonged contact with the oral virus from their partner make transmission more likely.
2. What are the odds my current boyfriend will get GHSV1 from me now that he has shown symptoms for OHSV1?
Very very unlikely.
3. Is it likely he already caught GHSV1 now from me and just only showed symptoms orally?
No, if he gets sores in his nose, he already had this – he didn’t get it from you. The virus just traveled on a slightly different nerve to get to his lip rather than his nose.
4. Will the antibodies from his cold sore prevent him from getting GHSV infection now?
Very likely they will. I have only seen one case in person of someone getting HSV 1 genitally after having a cold sore orally and one person online reported to me that it had happened to them. This is in 40 years of practice. So is it possible? Yes. Is it likely? Not at all.